diff --git a/webapp/controller/MallController.class.php b/webapp/controller/MallController.class.php
index 559ce8f6..774e38a8 100644
--- a/webapp/controller/MallController.class.php
+++ b/webapp/controller/MallController.class.php
@@ -120,28 +120,20 @@ class MallController extends BaseAuthedController {
             return;
         }
         $itemId = getReqVal('item_id', '');
-        $amount = getReqVal('amount', '');
+        $amount = intval(getReqVal('amount', ''), 10);
         $currency = getReqVal('currency', '');
         $priceBn = phpcommon\bnInit(getReqVal('price', ''));
         if ($itemId != V_ITEM_GOLD) {
             $this->_rspErr(1, 'only support gold');
             return;
         }
-        if (!$this->checkPrice($priceBn)) {
-            return;
-        }
-        if (empty($amount)) {
-            $this->_rspErr(1, 'amount not found');
-            return;
-        }
-        if (!is_numeric($amount)) {
-            $this->_rspErr(1, 'amount must be number');
-            return;
-        }
         if ($amount <= 0) {
             $this->_rspErr(1, 'amount must > 0');
             return;
         }
+        if (!$this->checkPrice($priceBn)) {
+            return;
+        }
         if (!in_array(
             $currency,
             array(