diff --git a/Assets/YooAsset/Runtime/DiagnosticSystem/DiagnosticBundleInfo.cs b/Assets/YooAsset/Runtime/DiagnosticSystem/DiagnosticBundleInfo.cs
index 5f43a0b9..10382121 100644
--- a/Assets/YooAsset/Runtime/DiagnosticSystem/DiagnosticBundleInfo.cs
+++ b/Assets/YooAsset/Runtime/DiagnosticSystem/DiagnosticBundleInfo.cs
@@ -21,7 +21,7 @@ namespace YooAsset
         public int ReferenceCount;
 
         /// <summary>
-        /// 当前状态
+        /// 资源包的加载状态
         /// </summary>
         public string Status;
 
diff --git a/Assets/YooAsset/Runtime/DiagnosticSystem/DiagnosticOperationInfo.cs b/Assets/YooAsset/Runtime/DiagnosticSystem/DiagnosticOperationInfo.cs
index 9bdd66df..76c3edac 100644
--- a/Assets/YooAsset/Runtime/DiagnosticSystem/DiagnosticOperationInfo.cs
+++ b/Assets/YooAsset/Runtime/DiagnosticSystem/DiagnosticOperationInfo.cs
@@ -21,7 +21,7 @@ namespace YooAsset
         public string OperationDesc;
 
         /// <summary>
-        ///异步操作的优先级
+        /// 异步操作的优先级
         /// </summary>
         public uint Priority;
 
@@ -36,12 +36,12 @@ namespace YooAsset
         public long ElapsedMS;
 
         /// <summary>
-        /// 当前进度
+        /// 异步操作的执行进度
         /// </summary>
         public float Progress;
 
         /// <summary>
-        /// 当前状态
+        /// 异步操作的执行状态
         /// </summary>
         public string Status;
 
diff --git a/Assets/YooAsset/Runtime/DiagnosticSystem/DiagnosticProviderInfo.cs b/Assets/YooAsset/Runtime/DiagnosticSystem/DiagnosticProviderInfo.cs
index 44999439..2065fbf2 100644
--- a/Assets/YooAsset/Runtime/DiagnosticSystem/DiagnosticProviderInfo.cs
+++ b/Assets/YooAsset/Runtime/DiagnosticSystem/DiagnosticProviderInfo.cs
@@ -16,7 +16,7 @@ namespace YooAsset
         public string AssetPath;
 
         /// <summary>
-        /// 资源出生的场景
+        /// 资源加载时所在的场景
         /// </summary>
         public string OriginScene;
 
@@ -36,7 +36,7 @@ namespace YooAsset
         public int ReferenceCount;
 
         /// <summary>
-        /// 当前状态
+        /// 资源的加载状态
         /// </summary>
         public string Status;
 
diff --git a/Assets/YooAsset/Runtime/DiagnosticSystem/DiagnosticReport.cs b/Assets/YooAsset/Runtime/DiagnosticSystem/DiagnosticReport.cs
index 811a1e00..1757db46 100644
--- a/Assets/YooAsset/Runtime/DiagnosticSystem/DiagnosticReport.cs
+++ b/Assets/YooAsset/Runtime/DiagnosticSystem/DiagnosticReport.cs
@@ -28,16 +28,20 @@ namespace YooAsset
         public List<DiagnosticPackageData> PackageDataList = new List<DiagnosticPackageData>(10);
 
         /// <summary>
-        /// 序列化
+        /// 序列化诊断报告为字节数组
         /// </summary>
+        /// <param name="report">要序列化的诊断报告</param>
+        /// <returns>UTF-8 编码的 JSON 字节数组</returns>
         public static byte[] Serialize(DiagnosticReport report)
         {
             return Encoding.UTF8.GetBytes(JsonUtility.ToJson(report));
         }
 
         /// <summary>
-        /// 反序列化
+        /// 从字节数组反序列化诊断报告
         /// </summary>
+        /// <param name="data">UTF-8 编码的 JSON 字节数组</param>
+        /// <returns>反序列化后的诊断报告</returns>
         public static DiagnosticReport Deserialize(byte[] data)
         {
             return JsonUtility.FromJson<DiagnosticReport>(Encoding.UTF8.GetString(data));
diff --git a/Assets/YooAsset/Runtime/DiagnosticSystem/EDebugCommandType.cs b/Assets/YooAsset/Runtime/DiagnosticSystem/EDebugCommandType.cs
index 9da5c9e7..6dd71ad5 100644
--- a/Assets/YooAsset/Runtime/DiagnosticSystem/EDebugCommandType.cs
+++ b/Assets/YooAsset/Runtime/DiagnosticSystem/EDebugCommandType.cs
@@ -1,6 +1,9 @@
 
 namespace YooAsset
 {
+    /// <summary>
+    /// 远程调试命令类型
+    /// </summary>
     internal enum EDebugCommandType
     {
         /// <summary>
diff --git a/Assets/YooAsset/Runtime/DiagnosticSystem/RemoteDebugCommand.cs b/Assets/YooAsset/Runtime/DiagnosticSystem/RemoteDebugCommand.cs
index 4dbc8446..f1384bba 100644
--- a/Assets/YooAsset/Runtime/DiagnosticSystem/RemoteDebugCommand.cs
+++ b/Assets/YooAsset/Runtime/DiagnosticSystem/RemoteDebugCommand.cs
@@ -23,16 +23,20 @@ namespace YooAsset
 
 
         /// <summary>
-        /// 序列化
+        /// 序列化命令为字节数组
         /// </summary>
+        /// <param name="command">要序列化的远程调试命令</param>
+        /// <returns>UTF-8 编码的 JSON 字节数组</returns>
         public static byte[] Serialize(RemoteDebugCommand command)
         {
             return Encoding.UTF8.GetBytes(JsonUtility.ToJson(command));
         }
 
         /// <summary>
-        /// 反序列化
+        /// 从字节数组反序列化命令
         /// </summary>
+        /// <param name="data">UTF-8 编码的 JSON 字节数组</param>
+        /// <returns>反序列化后的远程调试命令</returns>
         public static RemoteDebugCommand Deserialize(byte[] data)
         {
             return JsonUtility.FromJson<RemoteDebugCommand>(Encoding.UTF8.GetString(data));
diff --git a/Assets/YooAsset/Runtime/DownloadSystem/DownloadFailureCounter.cs b/Assets/YooAsset/Runtime/DownloadSystem/DownloadFailureCounter.cs
index 968d5c99..8031d8bf 100644
--- a/Assets/YooAsset/Runtime/DownloadSystem/DownloadFailureCounter.cs
+++ b/Assets/YooAsset/Runtime/DownloadSystem/DownloadFailureCounter.cs
@@ -3,8 +3,12 @@ using System.Collections.Generic;
 namespace YooAsset
 {
     /// <summary>
-    /// 网络请求失败计数器
+    /// 网络请求失败计数器（诊断用）
     /// </summary>
+    /// <remarks>
+    /// 线程安全：内部使用 Dictionary 且未加锁，约定只在 Unity 主线程调用。
+    /// 如需在多线程/回调线程调用，请在外层加锁或改为并发容器实现。
+    /// </remarks>
     internal class DownloadFailureCounter
     {
 #if UNITY_EDITOR
@@ -18,11 +22,16 @@ namespace YooAsset
         /// <summary>
         /// 失败计数记录表
         /// </summary>
+        /// <remarks>
+        /// Key 格式：$"{packageName}_{eventName}"
+        /// </remarks>
         private static readonly Dictionary<string, int> _failureRecords = new Dictionary<string, int>(1000);
 
         /// <summary>
         /// 记录一次失败
         /// </summary>
+        /// <param name="packageName">资源包名称</param>
+        /// <param name="eventName">事件名称</param>
         public static void RecordFailure(string packageName, string eventName)
         {
             string key = $"{packageName}_{eventName}";
@@ -34,6 +43,9 @@ namespace YooAsset
         /// <summary>
         /// 获取失败次数
         /// </summary>
+        /// <param name="packageName">资源包名称</param>
+        /// <param name="eventName">事件名称</param>
+        /// <returns>失败次数，如果未记录过则返回 0</returns>
         public static int GetFailureCount(string packageName, string eventName)
         {
             string key = $"{packageName}_{eventName}";
diff --git a/Assets/YooAsset/Runtime/DownloadSystem/DownloadRequestArgs.cs b/Assets/YooAsset/Runtime/DownloadSystem/DownloadRequestArgs.cs
index f2c661b0..710f1d23 100644
--- a/Assets/YooAsset/Runtime/DownloadSystem/DownloadRequestArgs.cs
+++ b/Assets/YooAsset/Runtime/DownloadSystem/DownloadRequestArgs.cs
@@ -66,11 +66,22 @@ namespace YooAsset
         /// <summary>
         /// 自定义请求头（可选）
         /// </summary>
+        /// <remarks>
+        /// 使用 AddRequestHeader 方法添加请求头。
+        /// 注意：相同 key 重复添加会抛出异常。
+        /// </remarks>
         public Dictionary<string, string> Headers;
 
         /// <summary>
         /// 构造文件下载请求参数
         /// </summary>
+        /// <param name="url">请求地址</param>
+        /// <param name="savePath">文件保存路径</param>
+        /// <param name="timeout">响应超时时间（秒），0 表示不应用超时</param>
+        /// <param name="watchdogTimeout">看门狗超时时间（秒），0 表示禁用</param>
+        /// <param name="appendToFile">是否追加写入文件（用于断点续传）</param>
+        /// <param name="removeFileOnAbort">中止时是否删除目标文件</param>
+        /// <param name="resumeOffset">断点续传的起始字节位置</param>
         public DownloadFileRequestArgs(
             string url,
             string savePath,
@@ -139,11 +150,18 @@ namespace YooAsset
         /// <summary>
         /// 自定义请求头（可选）
         /// </summary>
+        /// <remarks>
+        /// 使用 AddRequestHeader 方法添加请求头。
+        /// 注意：相同 key 重复添加会抛出异常。
+        /// </remarks>
         public Dictionary<string, string> Headers;
 
         /// <summary>
         /// 构造数据下载请求参数
         /// </summary>
+        /// <param name="url">请求地址</param>
+        /// <param name="timeout">响应超时时间（秒），0 表示不应用超时</param>
+        /// <param name="watchdogTimeout">看门狗超时时间（秒），0 表示禁用</param>
         public DownloadDataRequestArgs(string url, int timeout, int watchdogTimeout)
         {
             URL = url;
@@ -219,11 +237,21 @@ namespace YooAsset
         /// <summary>
         /// 自定义请求头（可选）
         /// </summary>
+        /// <remarks>
+        /// 使用 AddRequestHeader 方法添加请求头。
+        /// 注意：相同 key 重复添加会抛出异常。
+        /// </remarks>
         public Dictionary<string, string> Headers;
 
         /// <summary>
         /// 构造 AssetBundle 下载请求参数
         /// </summary>
+        /// <param name="url">请求地址</param>
+        /// <param name="timeout">响应超时时间（秒），0 表示不应用超时</param>
+        /// <param name="watchdogTimeout">看门狗超时时间（秒），0 表示禁用</param>
+        /// <param name="disableUnityWebCache">是否禁用 Unity 内置缓存</param>
+        /// <param name="fileHash">文件哈希（启用缓存时必须提供）</param>
+        /// <param name="unityCrc">Unity CRC 校验值</param>
         public DownloadAssetBundleRequestArgs(
             string url,
             int timeout,
diff --git a/Assets/YooAsset/Runtime/DownloadSystem/DownloadSystemTools.cs b/Assets/YooAsset/Runtime/DownloadSystem/DownloadSystemTools.cs
index 7abad2e1..145aad0c 100644
--- a/Assets/YooAsset/Runtime/DownloadSystem/DownloadSystemTools.cs
+++ b/Assets/YooAsset/Runtime/DownloadSystem/DownloadSystemTools.cs
@@ -1,11 +1,19 @@
-
+
 namespace YooAsset
 {
+    /// <summary>
+    /// 下载系统工具类
+    /// </summary>
+    /// <remarks>
+    /// 提供跨平台的 URL 转换和判断功能。
+    /// </remarks>
     internal class DownloadSystemTools
     {
         /// <summary>
         /// 转换为本地文件请求地址
         /// </summary>
+        /// <param name="path">本地文件路径</param>
+        /// <returns>可用于 UnityWebRequest 的文件协议 URL</returns>
         public static string ToLocalURL(string path)
         {
             string url;
@@ -58,13 +66,15 @@ namespace YooAsset
             throw new System.NotSupportedException($"Platform '{UnityEngine.Application.platform}' is not supported.");
 #endif
 
-            // For some special cases when users have special characters in their devices, url paths can not be identified correctly.
+            // 处理特殊字符：用户设备路径可能包含特殊字符导致 URL 无法正确识别
             return url.Replace("+", "%2B").Replace("#", "%23").Replace("?", "%3F");
         }
 
         /// <summary>
-        /// 是否请求的本地文件
+        /// 判断是否为本地文件 URL
         /// </summary>
+        /// <param name="url">要判断的 URL</param>
+        /// <returns>如果是本地文件 URL 返回 true，否则返回 false</returns>
         public static bool IsLocalFileURL(string url)
         {
             //TODO UNITY_STANDALONE_OSX平台目前无法确定
diff --git a/Assets/YooAsset/Runtime/DownloadSystem/EDownloadRequestStatus.cs b/Assets/YooAsset/Runtime/DownloadSystem/EDownloadRequestStatus.cs
index 76d6ecca..357ad62b 100644
--- a/Assets/YooAsset/Runtime/DownloadSystem/EDownloadRequestStatus.cs
+++ b/Assets/YooAsset/Runtime/DownloadSystem/EDownloadRequestStatus.cs
@@ -29,6 +29,9 @@ namespace YooAsset
         /// <summary>
         /// 已中止
         /// </summary>
+        /// <remarks>
+        /// 可能由用户主动调用 AbortRequest() 或看门狗超时触发。
+        /// </remarks>
         Aborted,
     }
 }
diff --git a/Assets/YooAsset/Runtime/DownloadSystem/Interface/IDownloadBackend.cs b/Assets/YooAsset/Runtime/DownloadSystem/Interface/IDownloadBackend.cs
index ae056bc6..09bd7138 100644
--- a/Assets/YooAsset/Runtime/DownloadSystem/Interface/IDownloadBackend.cs
+++ b/Assets/YooAsset/Runtime/DownloadSystem/Interface/IDownloadBackend.cs
@@ -5,6 +5,10 @@ namespace YooAsset
     /// <summary>
     /// 下载后台接口
     /// </summary>
+    /// <remarks>
+    /// 不同网络库（UnityWebRequest / BestHTTP / 自研）实现该接口，用于创建具体下载请求。
+    /// 每个后台实例是独立的，不共享全局状态。
+    /// </remarks>
     internal interface IDownloadBackend : IDisposable
     {
         /// <summary>
diff --git a/Assets/YooAsset/Runtime/DownloadSystem/Interface/IDownloadRequest.cs b/Assets/YooAsset/Runtime/DownloadSystem/Interface/IDownloadRequest.cs
index 73b1af31..f7712ac6 100644
--- a/Assets/YooAsset/Runtime/DownloadSystem/Interface/IDownloadRequest.cs
+++ b/Assets/YooAsset/Runtime/DownloadSystem/Interface/IDownloadRequest.cs
@@ -5,6 +5,9 @@ namespace YooAsset
     /// <summary>
     /// 可轮询的下载请求接口
     /// </summary>
+    /// <remarks>
+    /// 上层通常在每帧检查 IsDone 属性，完成后读取结果并调用 Dispose() 释放资源。
+    /// </remarks>
     internal interface IDownloadRequest : IDisposable
     {
         /// <summary>
@@ -15,6 +18,9 @@ namespace YooAsset
         /// <summary>
         /// 是否完成（成功/失败/中止）
         /// </summary>
+        /// <remarks>
+        /// 注意：访问此属性时会自动调用 PollingRequest() 进行轮询。
+        /// </remarks>
         bool IsDone { get; }
 
         /// <summary>
diff --git a/Assets/YooAsset/Runtime/DownloadSystem/UnityWebBackend/UnityWebRequestCreator.cs b/Assets/YooAsset/Runtime/DownloadSystem/UnityWebBackend/UnityWebRequestCreator.cs
index 75880dfb..dca8a8f9 100644
--- a/Assets/YooAsset/Runtime/DownloadSystem/UnityWebBackend/UnityWebRequestCreator.cs
+++ b/Assets/YooAsset/Runtime/DownloadSystem/UnityWebBackend/UnityWebRequestCreator.cs
@@ -3,7 +3,14 @@ using UnityEngine.Networking;
 namespace YooAsset
 {
     /// <summary>
-    /// 自定义下载器的请求委托
+    /// 自定义 UnityWebRequest 创建委托
     /// </summary>
+    /// <remarks>
+    /// 用于自定义 UnityWebRequest 的创建方式，例如添加证书验证、代理设置等。
+    /// 通过 UnityWebRequestBackend 构造函数传入。
+    /// </remarks>
+    /// <param name="url">请求地址</param>
+    /// <param name="method">HTTP 方法（如 GET、HEAD）</param>
+    /// <returns>自定义配置的 UnityWebRequest 实例</returns>
     public delegate UnityWebRequest UnityWebRequestCreator(string url, string method);
 }
diff --git a/Assets/YooAsset/Runtime/DownloadSystem/UnityWebRequest/UnityWebRequestBase.cs b/Assets/YooAsset/Runtime/DownloadSystem/UnityWebRequest/UnityWebRequestBase.cs
index 18136bd6..92790b40 100644
--- a/Assets/YooAsset/Runtime/DownloadSystem/UnityWebRequest/UnityWebRequestBase.cs
+++ b/Assets/YooAsset/Runtime/DownloadSystem/UnityWebRequest/UnityWebRequestBase.cs
@@ -273,7 +273,7 @@ namespace YooAsset
         }
 
         /// <summary>
-        /// 释放资源
+        /// 清理 WebRequest 资源
         /// </summary>
         private void CleanupWebRequest()
         {