In order to improve the robustness of symmetrical sixphase permanent magnet synchronous motor to parameter variation and load disturbance, a symmetrical sixphase permanent magnet synchronous motor speed system was proposed based on integral sliding mode surface. The stability of integral sliding mode controller was proved by Lyapunov theorem, and the performance of the controller was further analyzed. Simulation results showed that, the proposed algorithm had better antiinterference ability and stability compared with PI control algorithm.