With each wheel independently steered by electric motors instead of the steering mechanism in a traditional automobile, Four Wheel Independent Steering (4WIS) has control maneuverability and flexibility. Considering with the movement of four wheels in the process of steering, the steering centers of four wheels for two-axle car do not coincide, which may result in the wheels cannot move harmoniously, and lead to tire wire badly, steering instability and so on. For solving this problem, an optimization control method for Four Wheel Independent Steering (4WIS) electric vehicle based on the coincidence degree of wheel steering centers is proposed in this paper. Firstly, establishing the vehicle model of the four-wheel independent steering vehicle to get the coordinates of the trajectory and yaw angle of the vehicle in global coordinate system, and the sideslip angle of vehicle center of mass and other related parameters. The corresponding simulation model in MATLAB/Simulink software is also established. Next, the formula of the wheel steering center is derived base on the Multi-body Dynamics. Then, the coincidence degree of wheel steering centers is defined as the evaluation index, which can be used to describe and evaluate the performance of the coordination for wheels' movement. Lastly, the coincidence degree and related performance index for 4WIS vehicle steering system is performed as the optimization target for vehicles to achieve the optimal control by network predictive control algorithm. The simulation results show that compared with four wheel steering vehicle with proportional control and traditional front-wheel steering vehicle, the active four-wheel-steering vehicle under optimal control can achieve the control objective of both reducing the coincidence degree of wheel steering centers and sideslip angle of vehicle center of mass, and improve the steering response characteristics of vehicles.