A novel PMSM speed control strategy based on nonlinear active disturbance rejection control was proposed to solve the problems of poor anti-load disturbance ability and speed overshoot in PMSM servo system. By analyzing the disturbance mechanism of the servo system, the traditional PI controller is replaced by a nonlinear active disturbance rejection controller in the speed loop. The contradiction between response speed and overshoot is overcome by smoothing the given speed with tracking-differentiator, and the response capability of the system is improved. The second order extended state observer is introduced to estimate and compensate the external disturbance and improve the anti-interference ability of the system. Through nonlinear state error feedback control law, the nonlinear control of "small error with large gain, large error with small gain" is used to improve the control precision of the system. Simulation results show that the system has the characteristics of fast response, no overshoot, strong ability to resist load disturbance, and strong robustness to load change and speed change, which verifies the effectiveness of the strategy