diff --git a/unipay/providers/alipay.py b/unipay/providers/alipay.py
index d754487..89495c6 100644
--- a/unipay/providers/alipay.py
+++ b/unipay/providers/alipay.py
@@ -98,7 +98,7 @@ class AlipayGateway(Gateway):
 			"product_code": "QUICK_WAP_WAY"
 		}
 		method='alipay.trade.page.pay'
-		if data._is_mobile:
+		if payload._is_mobile:
 			method = 'alipay.trade.wap.pay'
 		params = {
 			"app_id": self.app_id,