diff --git a/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadBackend/UnityWebRequestBackend.cs b/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadBackend/UnityWebRequestBackend.cs
index 6e874240..394aaed9 100644
--- a/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadBackend/UnityWebRequestBackend.cs
+++ b/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadBackend/UnityWebRequestBackend.cs
@@ -12,7 +12,7 @@ namespace YooAsset
     /// </remarks>
     internal sealed class UnityWebRequestBackend : IDownloadBackend
     {
-        private readonly UnityWebRequestDelegate _webRequestCreator;
+        private readonly UnityWebRequestCreator _webRequestCreator;
 
         /// <summary>
         /// 后端名称
@@ -36,7 +36,7 @@ namespace YooAsset
         /// 自定义 UnityWebRequest 创建委托（可选）。
         /// 如果为 null，则使用默认的 UnityWebRequest 构造方式。
         /// </param>
-        public UnityWebRequestBackend(UnityWebRequestDelegate webRequestCreator)
+        public UnityWebRequestBackend(UnityWebRequestCreator webRequestCreator)
         {
             _webRequestCreator = webRequestCreator;
         }
diff --git a/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadBackend/UnityWebRequestCreator.cs b/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadBackend/UnityWebRequestCreator.cs
new file mode 100644
index 00000000..c982a434
--- /dev/null
+++ b/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadBackend/UnityWebRequestCreator.cs
@@ -0,0 +1,10 @@
+using UnityEngine.Networking;
+using UnityEngine;
+
+namespace YooAsset
+{
+    /// <summary>
+    /// 自定义下载器的请求委托
+    /// </summary>
+    public delegate UnityWebRequest UnityWebRequestCreator(string url);
+}
diff --git a/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadBackend/UnityWebRequestCreator.cs.meta b/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadBackend/UnityWebRequestCreator.cs.meta
new file mode 100644
index 00000000..aeeb570e
--- /dev/null
+++ b/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadBackend/UnityWebRequestCreator.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 0fa3e6346decc4d4db3b03e6ae93e57a
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadRequest/UnityWebRequestAssetBundleDownloader.cs b/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadRequest/UnityWebRequestAssetBundleDownloader.cs
index 15935313..8be0c9c2 100644
--- a/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadRequest/UnityWebRequestAssetBundleDownloader.cs
+++ b/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadRequest/UnityWebRequestAssetBundleDownloader.cs
@@ -26,7 +26,7 @@ namespace YooAsset
         /// </summary>
         /// <param name="args">AssetBundle 下载参数</param>
         /// <param name="webRequestCreator">UnityWebRequest 创建器（可选）</param>
-        public UnityWebRequestAssetBundleDownloader(DownloadAssetBundleRequestArgs args, UnityWebRequestDelegate webRequestCreator)
+        public UnityWebRequestAssetBundleDownloader(DownloadAssetBundleRequestArgs args, UnityWebRequestCreator webRequestCreator)
             : base(args.URL, webRequestCreator)
         {
             _args = args;
@@ -75,17 +75,12 @@ namespace YooAsset
             }
             else
             {
-                // 使用 Unity 缓存（需要 FileHash）
-                // The file hash defining the version of the asset bundle.
+                // 使用 Unity 缓存
+                // 说明：The file hash defining the version of the asset bundle.
                 Hash128 fileHash = Hash128.Parse(_args.FileHash);
                 handler = new DownloadHandlerAssetBundle(URL, fileHash, _args.UnityCRC);
             }
 
-#if UNITY_2020_3_OR_NEWER
-            // 禁用自动加载，允许手动控制加载时机
-            handler.autoLoadAssetBundle = false;
-#endif
-
             return handler;
         }
     }
diff --git a/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadRequest/UnityWebRequestBytesDownloader.cs b/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadRequest/UnityWebRequestBytesDownloader.cs
index 001932ae..f12b2857 100644
--- a/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadRequest/UnityWebRequestBytesDownloader.cs
+++ b/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadRequest/UnityWebRequestBytesDownloader.cs
@@ -23,7 +23,7 @@ namespace YooAsset
         /// </summary>
         /// <param name="args">数据下载参数</param>
         /// <param name="webRequestCreator">UnityWebRequest 创建器（可选）</param>
-        public UnityWebRequestBytesDownloader(DownloadDataRequestArgs args, UnityWebRequestDelegate webRequestCreator)
+        public UnityWebRequestBytesDownloader(DownloadDataRequestArgs args, UnityWebRequestCreator webRequestCreator)
             : base(args.URL, webRequestCreator)
         {
             _args = args;
diff --git a/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadRequest/UnityWebRequestDownloaderBase.cs b/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadRequest/UnityWebRequestDownloaderBase.cs
index 9824a5a6..60d1c078 100644
--- a/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadRequest/UnityWebRequestDownloaderBase.cs
+++ b/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadRequest/UnityWebRequestDownloaderBase.cs
@@ -13,7 +13,7 @@ namespace YooAsset
     /// </remarks>
     internal abstract class UnityWebRequestDownloaderBase : IDownloadRequest
     {
-        private readonly UnityWebRequestDelegate _webRequestCreator;
+        private readonly UnityWebRequestCreator _webRequestCreator;
         protected UnityWebRequest _webRequest;
 
         // 看门狗相关
@@ -76,7 +76,7 @@ namespace YooAsset
         /// </summary>
         /// <param name="url">请求地址</param>
         /// <param name="webRequestCreator">UnityWebRequest 创建器（可选）</param>
-        protected UnityWebRequestDownloaderBase(string url, UnityWebRequestDelegate webRequestCreator)
+        protected UnityWebRequestDownloaderBase(string url, UnityWebRequestCreator webRequestCreator)
         {
             URL = url;
             _webRequestCreator = webRequestCreator;
diff --git a/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadRequest/UnityWebRequestFileDownloader.cs b/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadRequest/UnityWebRequestFileDownloader.cs
index 11273e45..342a96ae 100644
--- a/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadRequest/UnityWebRequestFileDownloader.cs
+++ b/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadRequest/UnityWebRequestFileDownloader.cs
@@ -26,7 +26,7 @@ namespace YooAsset
         /// </summary>
         /// <param name="args">文件下载参数</param>
         /// <param name="webRequestCreator">UnityWebRequest 创建器（可选）</param>
-        public UnityWebRequestFileDownloader(DownloadFileRequestArgs args, UnityWebRequestDelegate webRequestCreator)
+        public UnityWebRequestFileDownloader(DownloadFileRequestArgs args, UnityWebRequestCreator webRequestCreator)
             : base(args.URL, webRequestCreator)
         {
             _args = args;
diff --git a/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadRequest/UnityWebRequestHeadDownloader.cs b/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadRequest/UnityWebRequestHeadDownloader.cs
index ef3e4ff3..62e13004 100644
--- a/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadRequest/UnityWebRequestHeadDownloader.cs
+++ b/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadRequest/UnityWebRequestHeadDownloader.cs
@@ -69,7 +69,7 @@ namespace YooAsset
         /// </summary>
         /// <param name="args">数据下载参数</param>
         /// <param name="webRequestCreator">UnityWebRequest 创建器（可选）</param>
-        public UnityWebRequestHeadDownloader(DownloadDataRequestArgs args, UnityWebRequestDelegate webRequestCreator)
+        public UnityWebRequestHeadDownloader(DownloadDataRequestArgs args, UnityWebRequestCreator webRequestCreator)
                             : base(args.URL, webRequestCreator)
         {
             _args = args;
diff --git a/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadRequest/UnityWebRequestTextDownloader.cs b/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadRequest/UnityWebRequestTextDownloader.cs
index 7c429afa..fee9fb06 100644
--- a/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadRequest/UnityWebRequestTextDownloader.cs
+++ b/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadRequest/UnityWebRequestTextDownloader.cs
@@ -23,7 +23,7 @@ namespace YooAsset
         /// </summary>
         /// <param name="args">数据下载参数</param>
         /// <param name="webRequestCreator">UnityWebRequest 创建器（可选）</param>
-        public UnityWebRequestTextDownloader(DownloadDataRequestArgs args, UnityWebRequestDelegate webRequestCreator)
+        public UnityWebRequestTextDownloader(DownloadDataRequestArgs args, UnityWebRequestCreator webRequestCreator)
             : base(args.URL, webRequestCreator)
         {
             _args = args;
diff --git a/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadRequest/VirtualFileDownloader.cs b/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadRequest/VirtualFileDownloader.cs
index 6cf5ab9b..96010902 100644
--- a/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadRequest/VirtualFileDownloader.cs
+++ b/Assets/YooAsset/Runtime/DownloadSystem/DefaultDownloadRequest/VirtualFileDownloader.cs
@@ -75,6 +75,7 @@ namespace YooAsset
         public VirtualFileDownloader(DownloadSimulateRequestArgs args)
         {
             _args = args;
+            URL = args.URL;
             Status = EDownloadRequestStatus.None;
         }
 
@@ -142,7 +143,7 @@ namespace YooAsset
 #if UNITY_2020_3_OR_NEWER
             return UnityEngine.Time.realtimeSinceStartupAsDouble;
 #else
-            return = UnityEngine.Time.realtimeSinceStartup;
+            return UnityEngine.Time.realtimeSinceStartup;
 #endif
         }
     }
diff --git a/Assets/YooAsset/Runtime/DownloadSystem/DownloadSystemHelper.cs b/Assets/YooAsset/Runtime/DownloadSystem/DownloadSystemHelper.cs
index c0f8fb54..f863affc 100644
--- a/Assets/YooAsset/Runtime/DownloadSystem/DownloadSystemHelper.cs
+++ b/Assets/YooAsset/Runtime/DownloadSystem/DownloadSystemHelper.cs
@@ -3,32 +3,8 @@ using UnityEngine;
 
 namespace YooAsset
 {
-    /// <summary>
-    /// 自定义下载器的请求委托
-    /// </summary>
-    public delegate UnityWebRequest UnityWebRequestDelegate(string url);
-
     internal class DownloadSystemHelper
     {
-#if UNITY_EDITOR
-        [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.SubsystemRegistration)]
-        private static void OnRuntimeInitialize()
-        {
-            UnityWebRequestCreater = null;
-        }
-#endif
-
-        public static UnityWebRequestDelegate UnityWebRequestCreater = null;
-        public static UnityWebRequest NewUnityWebRequestGet(string requestURL)
-        {
-            UnityWebRequest webRequest;
-            if (UnityWebRequestCreater != null)
-                webRequest = UnityWebRequestCreater.Invoke(requestURL);
-            else
-                webRequest = new UnityWebRequest(requestURL, UnityWebRequest.kHttpVerbGET);
-            return webRequest;
-        }
-
         /// <summary>
         /// 获取WWW加载本地资源的路径
         /// </summary>
diff --git a/Assets/YooAsset/Runtime/DownloadSystem/README.md b/Assets/YooAsset/Runtime/DownloadSystem/README.md
index 28551ceb..065f1b22 100644
--- a/Assets/YooAsset/Runtime/DownloadSystem/README.md
+++ b/Assets/YooAsset/Runtime/DownloadSystem/README.md
@@ -2,7 +2,7 @@
 
 ## 模块概述
 
-DownloadSystem 是 YooAsset 资源管理系统的**底层网络下载层**，负责处理所有 HTTP 网络请求。该模块提供了统一的下载接口抽象，支持文件下载、断点续传、并发控制、看门狗监控等功能。
+DownloadSystem 是 YooAsset 资源管理系统的**底层网络下载层**，负责处理所有 HTTP 网络请求。该模块提供了统一的下载接口抽象，支持文件下载、断点续传、并发请求（由上层调度）、看门狗监控等功能。
 
 ### 核心职责
 
@@ -14,13 +14,23 @@ DownloadSystem 是 YooAsset 资源管理系统的**底层网络下载层**，负
 
 ---
 
+## 边界与上层协作
+
+DownloadSystem 的职责是提供“可替换后端 + 统一请求接口 + 轮询式生命周期”的基础能力：
+
+- **本模块不负责并发队列/限流调度**：并发通常由上层同时创建多个 request 并自行控制并发数。
+- **本模块不负责重试/回退策略**：失败后的重试、切换 CDN、降级等策略通常由上层系统实现。
+- **本模块不负责持久化下载任务**：断点续传依赖本地已有文件与 `Range` 请求头，并由上层管理断点信息。
+
+---
+
 ## 设计目标
 
 | 目标 | 说明 |
 |------|------|
 | **可扩展性** | 支持可插拔的网络库后端（UnityWebRequest/BestHTTP/自研） |
 | **鲁棒性** | 看门狗超时保护、自动清理失败文件、完整错误信息 |
-| **高性能** | 轮询模式无阻塞、支持多并发请求 |
+| **高性能** | 轮询模式无阻塞、支持并发请求（并发数由上层调度） |
 | **易用性** | 流畅的参数构建 API、清晰的状态转换 |
 
 ---
@@ -70,7 +80,8 @@ DownloadSystem/
 │   └── IDownloadRequest.cs                   # 请求接口层次结构
 │
 ├── DefaultDownloadBackend/                   # 默认后端实现
-│   └── UnityWebRequestBackend.cs             # UnityWebRequest 后端
+│   ├── UnityWebRequestBackend.cs             # UnityWebRequest 后端
+│   └── UnityWebRequestCreator.cs             # UnityWebRequest 创建委托
 │
 ├── DefaultDownloadRequest/                   # 默认请求实现
 │   ├── UnityWebRequestDownloaderBase.cs      # 基础下载器（抽象类）
@@ -256,13 +267,15 @@ public struct DownloadSimulateRequestArgs
 - 无需手动调用 Update()，UnityWebRequest 自动驱动
 
 ```csharp
-// 自定义 UnityWebRequest 创建
-DownloadSystemHelper.UnityWebRequestCreater = (url) =>
+// 自定义 UnityWebRequest 创建（建议通过 backend 构造函数传入）
+UnityWebRequestCreator creator = (url) =>
 {
     var request = new UnityWebRequest(url, UnityWebRequest.kHttpVerbGET);
     // 自定义配置...
     return request;
 };
+
+IDownloadBackend backend = new UnityWebRequestBackend(creator);
 ```
 
 ### UnityWebRequestDownloaderBase
@@ -303,12 +316,11 @@ None ──► SendRequest() ──► Running ──► PollingRequest() ──
 ```csharp
 // 1. 创建后端和请求
 IDownloadBackend backend = new UnityWebRequestBackend();
-var args = new DownloadFileRequestArgs
-{
-    URL = "https://example.com/file.zip",
-    SavePath = "/path/to/save/file.zip",
-    Timeout = 30
-};
+var args = new DownloadFileRequestArgs(
+    url: "https://example.com/file.zip",
+    savePath: "/path/to/save/file.zip",
+    timeout: 30,
+    watchdogTime: 0);
 IDownloadFileRequest request = backend.CreateFileRequest(args);
 
 // 2. 发起并轮询
@@ -340,14 +352,14 @@ request.Dispose();
 // 获取已下载的文件大小
 long existingFileSize = new FileInfo(savePath).Length;
 
-var args = new DownloadFileRequestArgs
-{
-    URL = url,
-    SavePath = savePath,
-    ResumeFromBytes = existingFileSize,   // 断点位置
-    AppendToFile = true,                   // 追加写入
-    RemoveFileOnAbort = false              // 中止时保留文件
-};
+var args = new DownloadFileRequestArgs(
+    url: url,
+    savePath: savePath,
+    timeout: 30,
+    watchdogTime: 0,
+    appendToFile: true,                 // 追加写入
+    removeFileOnAbort: false,           // 中止时保留文件
+    resumeFromBytes: existingFileSize); // 断点位置
 
 IDownloadFileRequest request = backend.CreateFileRequest(args);
 request.SendRequest();
@@ -357,12 +369,11 @@ request.SendRequest();
 ### 看门狗保护
 
 ```csharp
-var args = new DownloadFileRequestArgs
-{
-    URL = url,
-    SavePath = path,
-    WatchdogTime = 30   // 30秒无数据自动中止
-};
+var args = new DownloadFileRequestArgs(
+    url: url,
+    savePath: path,
+    timeout: 30,
+    watchdogTime: 30); // 30秒无数据自动中止
 
 IDownloadFileRequest request = backend.CreateFileRequest(args);
 request.SendRequest();
@@ -382,10 +393,10 @@ if (request.Status == EDownloadRequestStatus.Aborted)
 ### HEAD 请求获取文件信息
 
 ```csharp
-var args = new DownloadDataRequestArgs
-{
-    URL = "https://example.com/file.zip"
-};
+var args = new DownloadDataRequestArgs(
+    url: "https://example.com/file.zip",
+    timeout: 30,
+    watchdogTime: 0);
 
 IDownloadHeadRequest request = backend.CreateHeadRequest(args);
 request.SendRequest();
@@ -408,10 +419,10 @@ if (request.Status == EDownloadRequestStatus.Succeed)
 ### 下载字节数据
 
 ```csharp
-var args = new DownloadDataRequestArgs
-{
-    URL = "https://example.com/data.json"
-};
+var args = new DownloadDataRequestArgs(
+    url: "https://example.com/data.json",
+    timeout: 30,
+    watchdogTime: 0);
 
 IDownloadBytesRequest request = backend.CreateBytesRequest(args);
 request.SendRequest();
@@ -519,9 +530,9 @@ VirtualFileDownloader (独立实现) ──► IDownloadFileRequest
 
 提供跨平台的工具函数：
 
-| 方法 | 说明 |
+| 成员 | 说明 |
 |------|------|
-| `NewUnityWebRequestGet()` | 创建 GET 请求（支持自定义工厂） |
+| `UnityWebRequestCreater` | 兼容保留的全局 UnityWebRequest 创建委托（默认文件系统不再读取，推荐改为 FileSystemParameters 注入） |
 | `ConvertToWWWPath()` | 转换本地路径为 WWW 协议 URL |
 | `IsRequestLocalFile()` | 判断是否本地文件请求 |
 
@@ -543,6 +554,9 @@ int count = WebRequestCounter.GetRequestFailedCount(packageName, eventName);
 
 1. **资源释放**：使用完毕后务必调用 `Dispose()` 释放资源
 2. **断点续传**：需要服务器支持 `Range` 请求头和 `206 Partial Content` 响应
+   - 若服务端不支持 Range 仍返回 200，全量内容可能会被追加写入，导致文件损坏
 3. **看门狗超时**：设置为 0 表示禁用，建议根据网络环境设置合理值
 4. **内存下载**：`IDownloadBytesRequest` 会将整个响应体加载到内存，不适合大文件
-5. **线程安全**：所有下载请求的创建和轮询应在主线程进行
+5. **驱动更新**：部分第三方网络库实现的 backend 可能需要每帧调用 `IDownloadBackend.Update()` 进行驱动
+6. **中止语义**：`Aborted` 可能来自用户主动 `AbortRequest()` 或看门狗超时；中止场景下 `HttpCode/Error` 可能为默认值（例如 0/空）
+7. **线程安全**：所有下载请求的创建和轮询应在主线程进行
diff --git a/Assets/YooAsset/Runtime/FileSystem/DefaultBuildinFileSystem/DefaultBuildinFileSystem.cs b/Assets/YooAsset/Runtime/FileSystem/DefaultBuildinFileSystem/DefaultBuildinFileSystem.cs
index 90ec6c8e..9e339af6 100644
--- a/Assets/YooAsset/Runtime/FileSystem/DefaultBuildinFileSystem/DefaultBuildinFileSystem.cs
+++ b/Assets/YooAsset/Runtime/FileSystem/DefaultBuildinFileSystem/DefaultBuildinFileSystem.cs
@@ -58,6 +58,11 @@ namespace YooAsset
         }
 
         #region 自定义参数
+        /// <summary>
+        /// 自定义参数：UnityWebRequest 创建委托
+        /// </summary>
+        public UnityWebRequestCreator WebRequestCreator { private set; get; }
+
         /// <summary>
         /// 自定义参数：覆盖安装缓存清理模式
         /// </summary>
@@ -178,7 +183,15 @@ namespace YooAsset
 
         public virtual void SetParameter(string name, object value)
         {
-            if (name == FileSystemParametersDefine.INSTALL_CLEAR_MODE)
+            if (name == FileSystemParametersDefine.DOWNLOAD_BACKEND)
+            {
+                DownloadBackend = (IDownloadBackend)value;
+            }
+            else if (name == FileSystemParametersDefine.UNITY_WEB_REQUEST_CREATOR)
+            {
+                WebRequestCreator = (UnityWebRequestCreator)value;
+            }
+            else if (name == FileSystemParametersDefine.INSTALL_CLEAR_MODE)
             {
                 InstallClearMode = (EOverwriteInstallClearMode)value;
             }
@@ -239,12 +252,14 @@ namespace YooAsset
 
             // 创建默认的下载后台接口
             if (DownloadBackend == null)
-                DownloadBackend = new UnityWebRequestBackend(DownloadSystemHelper.UnityWebRequestCreater);
+                DownloadBackend = new UnityWebRequestBackend(WebRequestCreator);
 
             // 创建解压文件系统
             var remoteServices = new DefaultUnpackRemoteServices(_packageRoot);
             _unpackFileSystem = new DefaultUnpackFileSystem();
             _unpackFileSystem.SetParameter(FileSystemParametersDefine.REMOTE_SERVICES, remoteServices);
+            _unpackFileSystem.SetParameter(FileSystemParametersDefine.DOWNLOAD_BACKEND, DownloadBackend);
+            _unpackFileSystem.SetParameter(FileSystemParametersDefine.UNITY_WEB_REQUEST_CREATOR, WebRequestCreator);
             _unpackFileSystem.SetParameter(FileSystemParametersDefine.INSTALL_CLEAR_MODE, InstallClearMode);
             _unpackFileSystem.SetParameter(FileSystemParametersDefine.FILE_VERIFY_LEVEL, FileVerifyLevel);
             _unpackFileSystem.SetParameter(FileSystemParametersDefine.FILE_VERIFY_MAX_CONCURRENCY, FileVerifyMaxConcurrency);
@@ -255,6 +270,17 @@ namespace YooAsset
         }
         public virtual void OnDestroy()
         {
+            if (_unpackFileSystem != null)
+            {
+                _unpackFileSystem.OnDestroy();
+                _unpackFileSystem = null;
+            }
+
+            if (DownloadBackend != null)
+            {
+                DownloadBackend.Dispose();
+                DownloadBackend = null;
+            }
         }
 
         public virtual bool Belong(PackageBundle bundle)
@@ -481,4 +507,4 @@ namespace YooAsset
         }
         #endregion
     }
-}
\ No newline at end of file
+}
diff --git a/Assets/YooAsset/Runtime/FileSystem/DefaultCacheFileSystem/DefaultCacheFileSystem.cs b/Assets/YooAsset/Runtime/FileSystem/DefaultCacheFileSystem/DefaultCacheFileSystem.cs
index 98f976aa..849abfe0 100644
--- a/Assets/YooAsset/Runtime/FileSystem/DefaultCacheFileSystem/DefaultCacheFileSystem.cs
+++ b/Assets/YooAsset/Runtime/FileSystem/DefaultCacheFileSystem/DefaultCacheFileSystem.cs
@@ -60,6 +60,11 @@ namespace YooAsset
         }
 
         #region 自定义参数
+        /// <summary>
+        /// 自定义参数：UnityWebRequest 创建委托
+        /// </summary>
+        public UnityWebRequestCreator WebRequestCreator { private set; get; }
+
         /// <summary>
         /// 自定义参数：远程服务接口的实例类
         /// </summary>
@@ -237,7 +242,15 @@ namespace YooAsset
 
         public virtual void SetParameter(string name, object value)
         {
-            if (name == FileSystemParametersDefine.REMOTE_SERVICES)
+            if (name == FileSystemParametersDefine.DOWNLOAD_BACKEND)
+            {
+                DownloadBackend = (IDownloadBackend)value;
+            }
+            else if (name == FileSystemParametersDefine.UNITY_WEB_REQUEST_CREATOR)
+            {
+                WebRequestCreator = (UnityWebRequestCreator)value;
+            }
+            else if (name == FileSystemParametersDefine.REMOTE_SERVICES)
             {
                 RemoteServices = (IRemoteServices)value;
             }
@@ -334,7 +347,7 @@ namespace YooAsset
 
             // 创建默认的下载后台接口
             if (DownloadBackend == null)
-                DownloadBackend = new UnityWebRequestBackend(DownloadSystemHelper.UnityWebRequestCreater);
+                DownloadBackend = new UnityWebRequestBackend(WebRequestCreator);
         }
         public virtual void OnDestroy()
         {
@@ -343,6 +356,12 @@ namespace YooAsset
                 DownloadScheduler.Dispose();
                 DownloadScheduler = null;
             }
+
+            if (DownloadBackend != null)
+            {
+                DownloadBackend.Dispose();
+                DownloadBackend = null;
+            }
         }
 
         public virtual bool Belong(PackageBundle bundle)
@@ -673,4 +692,4 @@ namespace YooAsset
         }
         #endregion
     }
-}
\ No newline at end of file
+}
diff --git a/Assets/YooAsset/Runtime/FileSystem/DefaultEditorFileSystem/DefaultEditorFileSystem.cs b/Assets/YooAsset/Runtime/FileSystem/DefaultEditorFileSystem/DefaultEditorFileSystem.cs
index f975fce8..0412d547 100644
--- a/Assets/YooAsset/Runtime/FileSystem/DefaultEditorFileSystem/DefaultEditorFileSystem.cs
+++ b/Assets/YooAsset/Runtime/FileSystem/DefaultEditorFileSystem/DefaultEditorFileSystem.cs
@@ -44,6 +44,11 @@ namespace YooAsset
         }
 
         #region 自定义参数
+        /// <summary>
+        /// 自定义参数：UnityWebRequest 创建委托
+        /// </summary>
+        public UnityWebRequestCreator WebRequestCreator { private set; get; }
+
         /// <summary>
         /// 模拟WebGL平台模式
         /// </summary>
@@ -117,7 +122,15 @@ namespace YooAsset
 
         public virtual void SetParameter(string name, object value)
         {
-            if (name == FileSystemParametersDefine.VIRTUAL_WEBGL_MODE)
+            if (name == FileSystemParametersDefine.DOWNLOAD_BACKEND)
+            {
+                DownloadBackend = (IDownloadBackend)value;
+            }
+            else if (name == FileSystemParametersDefine.UNITY_WEB_REQUEST_CREATOR)
+            {
+                WebRequestCreator = (UnityWebRequestCreator)value;
+            }
+            else if (name == FileSystemParametersDefine.VIRTUAL_WEBGL_MODE)
             {
                 VirtualWebGLMode = Convert.ToBoolean(value);
             }
@@ -153,10 +166,15 @@ namespace YooAsset
 
             // 创建默认的下载后台接口
             if (DownloadBackend == null)
-                DownloadBackend = new UnityWebRequestBackend(DownloadSystemHelper.UnityWebRequestCreater);
+                DownloadBackend = new UnityWebRequestBackend(WebRequestCreator);
         }
         public virtual void OnDestroy()
         {
+            if (DownloadBackend != null)
+            {
+                DownloadBackend.Dispose();
+                DownloadBackend = null;
+            }
         }
 
         public virtual bool Belong(PackageBundle bundle)
@@ -247,4 +265,4 @@ namespace YooAsset
         }
         #endregion
     }
-}
\ No newline at end of file
+}
diff --git a/Assets/YooAsset/Runtime/FileSystem/DefaultWebRemoteFileSystem/DefaultWebRemoteFileSystem.cs b/Assets/YooAsset/Runtime/FileSystem/DefaultWebRemoteFileSystem/DefaultWebRemoteFileSystem.cs
index c7707d94..cfa668b9 100644
--- a/Assets/YooAsset/Runtime/FileSystem/DefaultWebRemoteFileSystem/DefaultWebRemoteFileSystem.cs
+++ b/Assets/YooAsset/Runtime/FileSystem/DefaultWebRemoteFileSystem/DefaultWebRemoteFileSystem.cs
@@ -43,6 +43,11 @@ namespace YooAsset
         }
 
         #region 自定义参数
+        /// <summary>
+        /// 自定义参数：UnityWebRequest 创建委托
+        /// </summary>
+        public UnityWebRequestCreator WebRequestCreator { private set; get; }
+
         /// <summary>
         /// 禁用Unity的网络缓存
         /// </summary>
@@ -109,7 +114,15 @@ namespace YooAsset
 
         public virtual void SetParameter(string name, object value)
         {
-            if (name == FileSystemParametersDefine.DISABLE_UNITY_WEB_CACHE)
+            if (name == FileSystemParametersDefine.DOWNLOAD_BACKEND)
+            {
+                DownloadBackend = (IDownloadBackend)value;
+            }
+            else if (name == FileSystemParametersDefine.UNITY_WEB_REQUEST_CREATOR)
+            {
+                WebRequestCreator = (UnityWebRequestCreator)value;
+            }
+            else if (name == FileSystemParametersDefine.DISABLE_UNITY_WEB_CACHE)
             {
                 DisableUnityWebCache = Convert.ToBoolean(value);
             }
@@ -136,10 +149,15 @@ namespace YooAsset
 
             // 创建默认的下载后台接口
             if (DownloadBackend == null)
-                DownloadBackend = new UnityWebRequestBackend(DownloadSystemHelper.UnityWebRequestCreater);
+                DownloadBackend = new UnityWebRequestBackend(WebRequestCreator);
         }
         public virtual void OnDestroy()
         {
+            if (DownloadBackend != null)
+            {
+                DownloadBackend.Dispose();
+                DownloadBackend = null;
+            }
         }
 
         public virtual bool Belong(PackageBundle bundle)
@@ -179,4 +197,4 @@ namespace YooAsset
         #region 内部方法
         #endregion
     }
-}
\ No newline at end of file
+}
diff --git a/Assets/YooAsset/Runtime/FileSystem/DefaultWebServerFileSystem/DefaultWebServerFileSystem.cs b/Assets/YooAsset/Runtime/FileSystem/DefaultWebServerFileSystem/DefaultWebServerFileSystem.cs
index 7c9b1a88..8b0af887 100644
--- a/Assets/YooAsset/Runtime/FileSystem/DefaultWebServerFileSystem/DefaultWebServerFileSystem.cs
+++ b/Assets/YooAsset/Runtime/FileSystem/DefaultWebServerFileSystem/DefaultWebServerFileSystem.cs
@@ -57,6 +57,11 @@ namespace YooAsset
         }
 
         #region 自定义参数
+        /// <summary>
+        /// 自定义参数：UnityWebRequest 创建委托
+        /// </summary>
+        public UnityWebRequestCreator WebRequestCreator { private set; get; }
+
         /// <summary>
         /// 禁用Unity的网络缓存
         /// </summary>
@@ -118,7 +123,15 @@ namespace YooAsset
 
         public virtual void SetParameter(string name, object value)
         {
-            if (name == FileSystemParametersDefine.DISABLE_UNITY_WEB_CACHE)
+            if (name == FileSystemParametersDefine.DOWNLOAD_BACKEND)
+            {
+                DownloadBackend = (IDownloadBackend)value;
+            }
+            else if (name == FileSystemParametersDefine.UNITY_WEB_REQUEST_CREATOR)
+            {
+                WebRequestCreator = (UnityWebRequestCreator)value;
+            }
+            else if (name == FileSystemParametersDefine.DISABLE_UNITY_WEB_CACHE)
             {
                 DisableUnityWebCache = Convert.ToBoolean(value);
             }
@@ -146,10 +159,15 @@ namespace YooAsset
 
             // 创建默认的下载后台接口
             if (DownloadBackend == null)
-                DownloadBackend = new UnityWebRequestBackend(DownloadSystemHelper.UnityWebRequestCreater);
+                DownloadBackend = new UnityWebRequestBackend(WebRequestCreator);
         }
         public virtual void OnDestroy()
         {
+            if (DownloadBackend != null)
+            {
+                DownloadBackend.Dispose();
+                DownloadBackend = null;
+            }
         }
 
         public virtual bool Belong(PackageBundle bundle)
@@ -237,4 +255,4 @@ namespace YooAsset
         }
         #endregion
     }
-}
\ No newline at end of file
+}
diff --git a/Assets/YooAsset/Runtime/FileSystem/FileSystemParametersDefine.cs b/Assets/YooAsset/Runtime/FileSystem/FileSystemParametersDefine.cs
index ae85ea29..73d28baf 100644
--- a/Assets/YooAsset/Runtime/FileSystem/FileSystemParametersDefine.cs
+++ b/Assets/YooAsset/Runtime/FileSystem/FileSystemParametersDefine.cs
@@ -13,6 +13,8 @@ namespace YooAsset
         public const string DISABLE_CATALOG_FILE = "DISABLE_CATALOG_FILE";
         public const string DISABLE_UNITY_WEB_CACHE = "DISABLE_UNITY_WEB_CACHE";
         public const string DISABLE_ONDEMAND_DOWNLOAD = "DISABLE_ONDEMAND_DOWNLOAD";
+        public const string UNITY_WEB_REQUEST_CREATOR = "UNITY_WEB_REQUEST_CREATOR";
+        public const string DOWNLOAD_BACKEND = "DOWNLOAD_BACKEND";
         public const string DOWNLOAD_MAX_CONCURRENCY = "DOWNLOAD_MAX_CONCURRENCY";
         public const string DOWNLOAD_MAX_REQUEST_PER_FRAME = "DOWNLOAD_MAX_REQUEST_PER_FRAME";
         public const string DOWNLOAD_WATCH_DOG_TIME = "DOWNLOAD_WATCH_DOG_TIME";
@@ -28,4 +30,4 @@ namespace YooAsset
         public const string COPY_LOCAL_FILE_SERVICES = "COPY_LOCAL_FILE_SERVICES";
         public const string UNPACK_FILE_SYSTEM_ROOT = "UNPACK_FILE_SYSTEM_ROOT";
     }
-}
\ No newline at end of file
+}
diff --git a/Assets/YooAsset/Runtime/FileSystem/README.md b/Assets/YooAsset/Runtime/FileSystem/README.md
index e6df0e99..85b304f8 100644
--- a/Assets/YooAsset/Runtime/FileSystem/README.md
+++ b/Assets/YooAsset/Runtime/FileSystem/README.md
@@ -354,6 +354,17 @@ var webRemoteParams = FileSystemParameters.CreateDefaultWebRemoteFileSystemParam
 ```csharp
 var cacheParams = FileSystemParameters.CreateDefaultCacheFileSystemParameters(remoteServices);
 
+// 设置 UnityWebRequest 创建委托（用于证书/代理/自定义 Header 等）
+cacheParams.AddParameter(FileSystemParametersDefine.UNITY_WEB_REQUEST_CREATOR, (UnityWebRequestCreator)((url) =>
+{
+    var request = new UnityEngine.Networking.UnityWebRequest(url, UnityEngine.Networking.UnityWebRequest.kHttpVerbGET);
+    // 自定义配置...
+    return request;
+}));
+
+// 设置自定义下载后端（若设置则不再创建默认 UnityWebRequestBackend）
+// cacheParams.AddParameter(FileSystemParametersDefine.DOWNLOAD_BACKEND, myDownloadBackend);
+
 // 设置文件校验级别
 cacheParams.AddParameter(FileSystemParametersDefine.FILE_VERIFY_LEVEL, EFileVerifyLevel.High);
 
diff --git a/Assets/YooAsset/Runtime/YooAssets.cs b/Assets/YooAsset/Runtime/YooAssets.cs
index 3f78aad6..490bb574 100644
--- a/Assets/YooAsset/Runtime/YooAssets.cs
+++ b/Assets/YooAsset/Runtime/YooAssets.cs
@@ -241,9 +241,10 @@ namespace YooAsset
         /// <summary>
         /// 设置下载系统参数，自定义下载请求
         /// </summary>
-        public static void SetDownloadSystemUnityWebRequest(UnityWebRequestDelegate createDelegate)
+        [Obsolete("This method is deprecated. Please use FileSystemParametersDefine.UNITY_WEB_REQUEST_CREATOR instead.", true)]
+        public static void SetDownloadSystemUnityWebRequest(UnityWebRequestCreator createDelegate)
         {
-            DownloadSystemHelper.UnityWebRequestCreater = createDelegate;
+            throw new NotImplementedException();
         }
 
         /// <summary>