According to an embodiment, a method for selecting an access network at user equipment in a mobile communication system includes step of receiving, from a base station, first setting information, and step of selecting the access network based on second setting information if the second setting information is received from the base station, or selecting the access network based on the first setting information if no second setting information is received. Using the proposed method, the user equipment can reduce user's inconvenience and save battery by blocking unnecessary offloading and wireless LAN scanning, and also can improve the quality of use and immediately respond to a cell change by preventing a ping-pong phenomenon.