In order to optimize the control performance of permanent magnet synchronous motor (PMSM) servo system, a compound control strategy based on load observer and integral terminal sliding mode controller is proposed. Firstly, a PMSM model considering load disturbance is established. Then, an integral terminal sliding mode controller is designed based on the sliding mode surface and reaching law. In order to suppress the load disturbance, a load torque observer is introduced, and it is proved that the system is stable and can converge in finite time through Lyapunov′s theorem. Finally, the simulation results show that this control strategy has higher position tracking accuracy, faster response speed and stronger antiload capability.