Once the traditional electric vehicle was refitted with distributed drive (4wid) system, the increasing of vehicle"s unsprung mass would significantly increase the steering resistance, as a result of that, the efficiency and accuracy of the original car"s steer-by-wire (SBW) system will be reduced. In order to solve this problem, taking BAIC-EV150 for example, this paper introduced a design of SBW controller for 4WID vehicles, and the corresponding refitting work of real vehicle were completed. The refitted vehicle adopted dual-motor , dual-controller to coordinate control. The difference value between the auxiliary torque and the resistance moment were token as the input of the controller. A fuzzy adaptive PID controller was used to calculate the compensation torque, aiming at controlling the additional motor output compensation torque to offset the increased steering resistance. Based on the joint simulation of CARSIM and MATLAB, the real vehicle test was carried out consequently, during which the response speed and precision of ordinary PID control and adaptive fuzzy PID control are compared. Simulation and experimental results show that the controller can meet the requirements of 4WID vehicle steering, and the dual-motor steering system based on fuzzy PID control is more responsive and more accurate than the single-motor steering system which under ordinary PID control.