A method of executing to battery power consumption between an access terminal (AT) and an access network (AN) in a wireless communication system is disclosed. More specifically, the method includes transmitting a notification message to the AN, receiving a confirmation message from the AN, and entering the power-saving mode according to the determined power saving mode. Here, the notification message includes at least one of battery life information and a power-saving mode request, and the confirmation message includes a determined power saving mode which is based on the at least one of battery life information and the power-saving mode request.