Aiming at the problem that the control accuracy of permanent magnet synchronous linear motor (PMSLM) needs to be improved, a speed disturbance control method based on improved sliding mode control is proposed. An improved reaching law function is designed to quantitatively prove the effectiveness of the proposed control law based on Lyapunov stability, and the effectiveness is verified by Matlab 2019A/Simulink. The experimental results show that the proposed method is superior to the sliding mode control (SMC) and model-free speed controller (MFC) methods in terms of speed fluctuation and settling time when the load increases or decreases suddenly. It is effective and practical.