A method for efficiently updating system information of a base station at a relay station of a broadband wireless access system and an apparatus for performing the method are disclosed. The method for updating system information of an advanced base station (ABS) at an advanced relay station (ARS) of a broadband wireless access system comprises receiving a first message, which includes changed information of the system information of the base station, from the base station; transmitting a second message for acknowledgment of the first message to the base station; and performing application for the changed information.