Permanent magnet synchronous linear motor (PMSLM) drives the load directly, and the motor performance is easily affected by internal and external disturbances, which makes the control performance poor. Sliding mode control (SMC) is a kind of discontinuous control with good robustness, but the chattering problem exists in traditional sliding mode. Aiming at this problem, an improved SMC is designed. Based on the exponential reaching law, the variable exponential integral power term, the power reaching law and the saturation function of state variables are introduced to realize the position SMC of PMSLM, and the chattering caused by the sliding mode is effectively reduced. The extended state observer (ESO) is used to observe the external load disturbance in real time, and the reaching law parameter in the sliding mode variable structure is reduced by adjusting the control quantity, so as to improve the control performance of the motor.