A method for updating system information in a broadband wireless communication system in which data is transmitted and received via a superframe, includes: receiving information from a base station by means of superframes including a primary superframe header (P-SFH) and a secondary superframe header (S-SFH), wherein the information including control information transmitted via an information element of the P-SFH (P-SFH IE) and system information transmitted via at least one of information element of a subpacket (SP) of the S-SFH (S-SFH SP IE); decoding the P-SFH IE, wherein the P-SFH IE including a scheduling information bitmap indicating a transmitted S-SFH SP IEs in the superframe, a change count (CC) of the S-SFH, and a SP change bitmap indicating changing status of the S-SFH SP IEs; comparing the received CC with a previously stored CC; checking the S-SFH SP change bitmap, if there is a difference between the received CC and the stored CC; and decoding and updating corresponding SP IE of the S-SFH based on the checking result.