diff --git a/lib/wechat.js b/lib/wechat.js
index bbf74828..bcbd4fc0 100644
--- a/lib/wechat.js
+++ b/lib/wechat.js
@@ -184,7 +184,7 @@ var respond = function (handler) {
       res.writeHead(200);
       // 响应空字符串，用于响应慢的情况，避免微信重试
       if (!content) {
-        return res.end();
+        return res.end('');
       }
       var xml = reply(content, message.ToUserName, message.FromUserName);
       if (!req.query.encrypt_type || req.query.encrypt_type === 'raw') {