edit

lib/Wechat.php

@@ -112,7 +112,7 @@ class Wechat extends Core
 			$order['partnerid'] = $this->config->GetMerchantId();
 			$order['package_string'] = 'Sign=WXPay';
 
-			$string = 'appid='.$this->config->GetAppId().'&partnerid='.$order['partnerid'].'&prepayid='.$order['prepay_id'].'&package='.$order['package'].'&noncestr='.$order['nonce_str'].'&timestamp='.$order['time'];
+			$string = 'appid='.$this->config->GetAppId().'&partnerid='.$order['partnerid'].'&prepayid='.$order['prepay_id'].'&package='.$order['package_string'].'&noncestr='.$order['nonce_str'].'&timestamp='.$order['time'];
 			if($order['sign_type'] == "MD5"){
 				$string = md5($string);
 			} else {