Disclosed is an apparatus and method for allocating downlink/uplink subchannels for a soft handover in a broadband wireless access communication system, wherein the method includes the steps of configuring FUSC subchannels based on a predetermined FUSC subchannel configuration scheme by using an equal seed value in all cells; allocating a predetermined number of FUSC subchannels of the configured FUSC subchannels as soft handover subchannels; and allocating remaining subchannels, except for the FUSC subchannels allocated as the first subchannels, as non-soft handover subchannels based on the FUSC subchannel configuration scheme by using a specific seed value.