The present invention relates to a method and an apparatus that supports a multi-carrier wireless access system for transmitting and receiving system information. The 1st embodiment of the present invention is a method for controlling a center frequency in a wireless access system comprising the steps of: receiving a control message including a 1st parameter which indicates a configuration of carrier groups and a 2nd parameter which indicates whether the center frequency is controlled from a base station; deriving the center frequency of carriers allocated to a mobile terminal by using the 1st parameter; and controlling the center frequency by using the 2nd parameter.