Aiming at the chattering problem of sliding mode control system for permanent magnet synchronous motor (PMSM),a control method based on a new saturation function,variable exponential approach rate and non-singular fast terminal sliding mode,was proposed,and its stability was proved by using Lyapunov inequality.Considering the impact of external load torque on system performance,a non-singular terminal sliding mode disturbance observer was established,by which the observed torque values were converted into torque current feedforward compensation to the input side of the current loop,avoiding significant sliding mode gain and overcoming the systems chattering problem when external disturbances were suddenly added.The simulation and experimental results show that the improved sliding mode controller combined with disturbance observer can effectively reduce system chattering and improve the dynamic response and anti-interference ability of the control system.