To improve the stability of permanent magnet synchronous motor (PMSM) with traditional integral sliding mode control (SMC) structure and improve the stability of the systema new integral weakening SMC structure is designed. Based on the traditional integral SMC structurethe boundary layer concept is introduced to weaken the integral outside the layer and soften the approaching motion of the motor. The advantages of this method are verified by Lyapunov function. Based on the integral weakening structurethe PMSM vector control models of the traditional and novel controllers are respectively built in MATLAB/Simulink for comparison and verification. The simulation analysis results show thatcompared with the traditional integral sliding mode controlthe designed SMC structure can effectively improve the steady-state error and stability of the system.