diff --git a/webapp/controller/MallController.class.php b/webapp/controller/MallController.class.php
index 3fc20a85..5859c397 100644
--- a/webapp/controller/MallController.class.php
+++ b/webapp/controller/MallController.class.php
@@ -1,5 +1,7 @@
 <?php
 
+require_once('phpcommon/bignumber.php');
+
 require_once('mt/Item.php');
 require_once('mt/Parameter.php');
 
@@ -28,6 +30,13 @@ class MallController extends BaseAuthedController {
     const PRICE_LOW = '1';
     const PRICE_HIGH = '111111111111111111111000000000000000000';
 
+    public function _handlePre()
+    {
+        parent::_handlePre();
+        $this->priceLowBn = phpcommon\bnInit(self::PRICE_LOW);
+        $this->priceHighBn = phpcommon\bnInit(self::PRICE_HIGH);
+    }
+
     public function productList()
     {
         $page = getReqVal('page', 0);