update

src/applet/app/controllers/CallBackController.php

@@ -173,7 +173,9 @@ class CallBackController extends \Phalcon\Mvc\Controller
         $this->logger($args, 'wxpayAsyncNotifyCallBack', true);
 
         if ($this->request->isPost()) {
-            $this->logger($_POST, 'wxpayAsyncNotifyCallBack_post', true);
+            $data = file_get_contents('php://input');
+            $data = json_decode($data, true);
+            $this->logger($data, 'wxpayAsyncNotifyCallBack_post', true);
         }
     }
 }