Aiming at the problems of large speed overshoot, slow approaching speed, poor stability and system chattering in the application of traditional SMC (sliding mode control) in PMSM (permanent magnet synchronous motor), a fuzzy sliding mode control method based on improved exponential reaching law was proposed. Firstly, the system state variables were introduced on the basis of the traditional exponential reaching law, so that the system reaching speed was related to the change of state variables. Secondly, by setting the fuzzy rules of the system state sliding surface and the exponential coefficient, the sliding mode parameters were adjusted in real time, so that the approaching process was dynamically controlled. At the same time, aiming at the problem that the symbol function sgn (s) was discontinuous in the switching process, it was improved so that the system can switch smoothly. Finally, the simulation results show that the proposed method has faster response speed, better anti-interference ability, better dynamic and static performance than the traditional exponential reaching law, and the effectiveness of the system is verified.