diff --git a/video-gen-api/app/api/v1/payments.py b/video-gen-api/app/api/v1/payments.py
index 490d2533..e3fc9277 100644
--- a/video-gen-api/app/api/v1/payments.py
+++ b/video-gen-api/app/api/v1/payments.py
@@ -167,7 +167,9 @@ async def wechat_callback(request: Request, db: AsyncSession = Depends(get_db)):
         
         # 使用 AES-GCM 解密
         try:
-            aesgcm = AESGCM(api_v3_key)
+            # API v3 key 需要转换为字节串
+            api_v3_key_bytes = api_v3_key.encode('utf-8')
+            aesgcm = AESGCM(api_v3_key_bytes)
             decrypted_str = aesgcm.decrypt(ciphertext, associated_data, nonce_str)
         except InvalidTag:
             logger.error("WeChat callback decryption failed: Invalid tag")