An apparatus and method for reducing power consumption in a mobile communication system are provided. The apparatus includes a time slicing processor. When a frame border of the last section for determining a burst reception end time is not detected during a burst reception operation, the time slicing processor receives a burst enough to restore the whole MPE-FEC frame to the former state or receives an early burst reception end request for notifying that it is impossible to restore the whole MPE-FEC frame to the former state, and terminates the burst reception process.