diff --git a/video-gen-api/app/services/payment.py b/video-gen-api/app/services/payment.py
index 43c232cc..49d6cf67 100644
--- a/video-gen-api/app/services/payment.py
+++ b/video-gen-api/app/services/payment.py
@@ -357,8 +357,7 @@ def _get_wechat_client(
     cert_serial_no: str,
     api_v3_key: str,
     appid: str,
-    notify_url: str = "",
-    cert_dir: str | None = None
+    notify_url: str = ""
 ):
     """Get or create a WeChat Pay client. Recreated if config changes."""
     global _wechat_client, _wechat_mch_id
@@ -368,6 +367,7 @@ def _get_wechat_client(
 
     try:
         from wechatpayv3 import WeChatPay, WeChatPayType
+        import os
     except ImportError:
         logger.error(
             "wechatpayv3 is not installed. "
@@ -376,8 +376,15 @@ def _get_wechat_client(
         return None
 
     try:
-        # 直接传入原始私钥，让 SDK 自己处理格式化
-        # SDK 内部已有 format_private_key 函数处理各种格式
+        # 创建并确保微信支付证书目录存在
+        wechat_cert_dir = os.path.abspath(os.path.join(
+            os.path.dirname(os.path.dirname(__file__)), 
+            "..", 
+            "storage", 
+            "wechat_certs"
+        ))
+        os.makedirs(wechat_cert_dir, exist_ok=True)
+        logger.info("WeChat Pay platform certificates will be stored in: %s", wechat_cert_dir)
         
         # 初始化微信支付客户端
         _wechat_client = WeChatPay(
@@ -388,13 +395,18 @@ def _get_wechat_client(
             appid=appid,
             apiv3_key=api_v3_key,
             notify_url=notify_url,
-            cert_dir=cert_dir,
+            cert_dir=wechat_cert_dir,
         )
         _wechat_mch_id = mch_id
         logger.info("WeChat Pay client initialized successfully")
         return _wechat_client
     except Exception as e:
-        logger.exception(f"Failed to initialize WeChat Pay client: {e}")
+        logger.exception(
+            "Failed to initialize WeChat Pay client: %s\n"
+            "Please double-check your merchant private key configuration.\n"
+            "It should be from apiclient_key.pem, NOT apiclient_cert.pem!",
+            e
+        )
         _wechat_client = None
         _wechat_mch_id = None
         return None