Objective To address the issue that the sliding mode control system based on the exponential reaching law cannot simultaneously balance the reaching speed and chattering an improved fast non-singular terminal sliding mode control system based on a novel reaching law is established. Methods First a novel reaching law is designed which can rapidly approach the sliding mode surface during the approaching stage and quickly converge upon reaching the surface. Based on this novel reaching law an improved fast non-singular terminal sliding mode controller is designed. Second since the motor may be affected by uncertain factors such as load disturbances during actual operation to enhance the anti-interference performance of the system a disturbance observer is designed to estimate the disturbances in the control system and the estimated disturbance values are fed back to the speed-loop sliding mode controller for disturbance compensation. Results A simulation model of the PMSM permanent magnet synchronous motor control system is built in MATLAB / Simulink for simulation verification. Conclusion The results indicate that compared with traditional sliding mode control the proposed control method can effectively reduce chattering and has a good dynamic response.