diff --git a/WePay/Order.php b/WePay/Order.php
index 91cb195..5040acb 100644
--- a/WePay/Order.php
+++ b/WePay/Order.php
@@ -87,7 +87,7 @@ class Order extends BasicWePay
     public function jsapiParams($prepayId)
     {
         $option = [];
-        $option["appId"] = $this->config->get('appid');
+        $option["appId"] = $this->config->get('sub_appid') ? $this->config->get('sub_appid') : $this->config->get('appid');
         $option["timeStamp"] = (string)time();
         $option["nonceStr"] = Tools::createNoncestr();
         $option["package"] = "prepay_id={$prepayId}";
@@ -172,4 +172,4 @@ class Order extends BasicWePay
         $url = 'https://api.mch.weixin.qq.com/payitil/report';
         return $this->callPostApi($url, $options);
     }
-}
\ No newline at end of file
+}