In order to improve the control performance of permanent magnet synchronous motor (PMSM) with exogenous disturbance, a disturbance observer (DOB)based backstepping control strategy for speed regulation is proposed in this paper. First, aiming at the dynamic disturbance originated from the external system of PMSM, a disturbance observer is constructed by using system state variables. The design problem of DOB is transformed into the stability problem of system error. Furthermore, based on Lyapunov stability theory, the existence condition based on linear matrix inequality and design method of DOB are obtained. Next, on the base of realtime reconstruction of the dynamic disturbance, a backstepping control strategy is designed, which makes the system has good performance of speed tracking, torque response and disturbance rejection. Finally, the effectiveness and feasibility of the designed system are verified by Matlab simulation and experiment results. The simulation results show that when the setting speed is 500 r/min, the time required for the motor starting to reach the steady state is shortened from 0.025 s to 0.008 s, and the peak speed of the motor is reduced from 680 r/min to 520 r/min compared with the traditional PID control. The DSPbased experimental results show that the proposed control strategy has the advantages of fast response, small overshoot, high steadystate accuracy, and can effectively reject the load disturbance.