diff --git a/src/Modules/TakeoutSaaS.Module.Storage/Providers/S3StorageProviderBase.cs b/src/Modules/TakeoutSaaS.Module.Storage/Providers/S3StorageProviderBase.cs
index 0745830..6251c01 100644
--- a/src/Modules/TakeoutSaaS.Module.Storage/Providers/S3StorageProviderBase.cs
+++ b/src/Modules/TakeoutSaaS.Module.Storage/Providers/S3StorageProviderBase.cs
@@ -60,6 +60,12 @@ public abstract class S3StorageProviderBase : IObjectStorageProvider, IDisposabl
     /// <inheritdoc />
     public virtual async Task<StorageUploadResult> UploadAsync(StorageUploadRequest request, CancellationToken cancellationToken = default)
     {
+        // 0. 兜底重置流位置，避免上游读取导致内容缺失
+        if (request.Content.CanSeek)
+        {
+            request.Content.Position = 0;
+        }
+
         // 1. 构建上传请求
         var putRequest = new PutObjectRequest
         {
@@ -67,9 +73,18 @@ public abstract class S3StorageProviderBase : IObjectStorageProvider, IDisposabl
             Key = request.ObjectKey,
             InputStream = request.Content,
             AutoCloseStream = false,
-            ContentType = request.ContentType
+            ContentType = request.ContentType,
+            DisableDefaultChecksumValidation = true,
+            UseChunkEncoding = false,
+            DisablePayloadSigning = true
         };
 
+        // 1.1 显式设置 Content-Length，避免 S3 SDK 对兼容网关使用 aws-chunked 导致对象内容被写入“chunk-signature”头而损坏
+        if (request.ContentLength > 0)
+        {
+            putRequest.Headers.ContentLength = request.ContentLength;
+        }
+
         foreach (var kv in request.Metadata)
         {
             putRequest.Metadata[kv.Key] = kv.Value;
@@ -167,17 +182,50 @@ public abstract class S3StorageProviderBase : IObjectStorageProvider, IDisposabl
     /// </summary>
     protected virtual IAmazonS3 CreateClient()
     {
+        // 1. 尽量推断鉴权 Region（腾讯云 COS 的 S3 兼容域名形如：cos.ap-beijing.myqcloud.com）
+        var authenticationRegion = ResolveAuthenticationRegion(ServiceUrl);
+
+        // 2. 构建客户端配置
         var config = new AmazonS3Config
         {
             ServiceURL = ServiceUrl,
             ForcePathStyle = ForcePathStyle,
-            UseHttp = !UseHttps
+            UseHttp = !UseHttps,
+            AuthenticationRegion = authenticationRegion
         };
 
+        // 3. 创建客户端并返回
         var credentials = new BasicAWSCredentials(AccessKey, SecretKey);
         return new AmazonS3Client(credentials, config);
     }
 
+    private static string? ResolveAuthenticationRegion(string serviceUrl)
+    {
+        // 1. 解析 URL
+        if (!Uri.TryCreate(serviceUrl, UriKind.Absolute, out var uri))
+        {
+            return null;
+        }
+
+        // 2. 提取 Host
+        var host = uri.Host;
+        if (string.IsNullOrWhiteSpace(host))
+        {
+            return null;
+        }
+
+        // 3. 按 COS 域名规则解析 Region
+        const string cosPrefix = "cos.";
+        const string cosSuffix = ".myqcloud.com";
+        if (host.StartsWith(cosPrefix, StringComparison.OrdinalIgnoreCase) &&
+            host.EndsWith(cosSuffix, StringComparison.OrdinalIgnoreCase))
+        {
+            var regionPart = host.Substring(cosPrefix.Length, host.Length - cosPrefix.Length - cosSuffix.Length);
+            return string.IsNullOrWhiteSpace(regionPart) ? null : regionPart;
+        }
+        return null;
+    }
+
     private IAmazonS3 Client => _client ??= CreateClient();
 
     /// <inheritdoc />