diff --git a/server/app.py b/server/app.py
index 6fb5342..11fd82f 100644
--- a/server/app.py
+++ b/server/app.py
@@ -387,11 +387,13 @@ def upload_avatar():
     
     # 验证文件类型
     allowed_extensions = {'png', 'jpg', 'jpeg', 'gif', 'webp'}
-    filename = secure_filename(file.filename)
-    if '.' not in filename:
+    
+    # 先从原始文件名获取扩展名
+    original_filename = file.filename
+    if '.' not in original_filename:
         return jsonify({'error': '无效的文件格式'}), 400
     
-    ext = filename.rsplit('.', 1)[1].lower()
+    ext = original_filename.rsplit('.', 1)[1].lower()
     if ext not in allowed_extensions:
         return jsonify({'error': '不支持的文件格式，请上传 PNG、JPG、GIF 或 WEBP 格式'}), 400