diff --git a/src/middleware/auth.js b/src/middleware/auth.js
index a5568323..e5a449b6 100644
--- a/src/middleware/auth.js
+++ b/src/middleware/auth.js
@@ -1388,7 +1388,8 @@ const globalRateLimit = async (req, res, next) =>
 
 // 📊 请求大小限制中间件
 const requestSizeLimit = (req, res, next) => {
-  const maxSize = 60 * 1024 * 1024 // 60MB
+  const MAX_SIZE_MB = parseInt(process.env.REQUEST_MAX_SIZE_MB || '60', 10)
+  const maxSize = MAX_SIZE_MB * 1024 * 1024
   const contentLength = parseInt(req.headers['content-length'] || '0')
 
   if (contentLength > maxSize) {