Method for operating electric power steering system of automobile

A method for operating an automobile electric power steering (EPS) system is provided. Whether or not the automatic adjustment of the steering angle is performed is decided based on a speed of the automobile and a rotational state of each wheel. A cooperative steering angle to cooperate a braking state of the automobile is set based on the decision and the speed of the automobile. A target steering angle is determined to adjust the steering angle based on the cooperative steering angle and a manual steering angle; and a feedback control on the steering angle is performed such that the steering angle of each wheel comes close to the determined target steering angle.