Aiming at the problem of poor responsiveness and synchronization of multi-motor control system, a multi-permanent magnet synchronous motor (PMSM) cooperative control strategy is proposed, taking the steering system of four-wheel independent drive road-rail vehicle as the controlled object. A new nonsingular rapid terminal sliding mode function combined with super-twisting algorithm is proposed. A super-twisting nonsingular sliding mode controller is designed to realize the coordinated control of multi-PMSM. The simulation model of the system is built on the platform of Matlab/Simulink, based on the self-developed electric road-rail vehicle, the vehicle experiment was carried out. The experimental results show that the super-twisting nonsingular rapid terminal sliding mode controller can effectively reduce the tracking error and synchronization error in the steering system, shorten the response time of the system, improve the control accuracy of the system, and achieve a better control effect.