An improved exponential reaching law sliding mode controller is designed to solve the problem of the speed overshoot and load disturbance in traditional permanent magnet synchronous motor(PMSM)control system.The adjustment function is added to the constant velocity term and exponential term of the traditional exponential reaching law,which makes the reaching law have faster convergence speed and better anti buffeting ability.In order to further improve the accuracy,a low-pass filtered load torque observer is introduced to compensate the observed value of load torque to reduce load disturbance.The simulation model is built on MATLAB/Simulink and compared with PI, traditional exponential reaching law and improved exponential reaching law without feedforward compensation.The simulation results show that compared with the other three control methods,the control strategy based on the improved sliding mode exponential reaching law and the torque feed-forward compensation has further improved the performance of reducing the overshoot instability of the speed and enhancing the anti load disturbance of the system.