Aiming at the chaotic behaviour of the permanent magnet synchronous motor (PMSM) emerged during its running process will affect the performance of speed control, this article submits a non-singular fast-terminal sliding mode method to suppress the chaotic phenomenon under the basic framework of PMSM vector control system. First, the chaos model of PMSM is presented and the existence of chaotic phenomenon is verified through simulation; Then, based on that, the non-singular fast-terminal sliding mode controller is designed to guarantee the robustness of the system, and the design of controller is simple and easy to be achieved; Last, through simulation, PMSM runs normally at first, then it produces chaotic phenomenon in some parameter and work conditions, by the addition of controller the chaos movement is eliminated, verifing the rapidity and effectiveness of this method.