The tracking of the actuator trajectory of the electrohydraulic servo system is easy to be disturbed by outside world,which leads to the instability of the control system.To solve this problem, a wavelet neural network PID control system was designed, and the control effect was verified by simulation. The schematic model of the electrohydraulic servo valve was established, the dynamic model of the valve core motion was established, and the dynamic equations of the control valve, hydraulic actuator and proportional relief valve were deduced respectively. Wavelet neural network was used to improve the traditional incremental PID controller, and the MATLAB software was used to simulate the improved control system; the trajectory of the hydraulic actuator before and after improvement was compared and analyzed. The results show that the two control methods can be used to realize the trajectory tracking of the hydraulic actuator well without sudden interference of the external waveform; in the case of the sudden interference of the external waveform, the trajectory of the hydraulic actuator controlled by incremental PID has a large error with the expected trajectory,but the trajectory of the hydraulic actuator controlled by the wavelet neural network has small error with the expected trajectory.The designed control system has a fast response speed and can adjust the control parameters online adaptively, which can effectively suppress the interference of the external environment to the control system and so as to improve the tracking accuracy of the hydraulic actuator trajectory