diff --git a/doc/Shop.py b/doc/Shop.py
index 331f0d85..224040c6 100644
--- a/doc/Shop.py
+++ b/doc/Shop.py
@@ -188,7 +188,7 @@ class Shop(object):
                     _common.RspHead(),
                     ['idx', 0, '每日精选的索引'],
                     ['refresh_info', '', '每日精选的刷新信息(格式:刷新次数/可刷新总数)'],
-                    ['cost', 0, '每日精选的当前刷新价格，null表示不可刷新'],
+                    ['cost', 0, '每日精选的当前刷新价格，-1表示不可刷新'],
                     ['!goods_list', [_common.DailySelectionGoods()], '每日精选列表'],
                 ]
             },