Disclosed are an electronic control brake system and a method for controlling the same. The method for controlling an electronic control brake system of a vehicle according to the present disclosure, in which a service brake is configured to provide a braking force by hydraulic pressure to each wheel and a drum in hat (DIH) brake is configured to provide a parking brake force to each of the wheels by pulling a parking cable, the method including determining whether rocking of the vehicle occurs due to a weight shift of the vehicle at the DIH brake on the basis of operation information of an electronic parking brake (EPB) system configured to adjust a braking force of the DIH brake, state information of a transmission gear, and state information of a brake pedal; and when the rocking of the vehicle is determined to occur, automatically operating the service brake.