Due to the non-linear factors and uncertain external interference in the hydraulic system of the cylinder cover of a ship,it is difficult to guarantee the control accuracy and smoothness of the cylinder cover opening and closing process.In order to improve the control accuracy and stability of the cover opening and closing process,based on the auto disturbance rejection control method,the study of the process control of the cover opening and closing process was carried out.The simulation and experiment results show that compared with traditional PID controller,using the proposed method,the trajectory tracking accuracy of the cover opening and closing process is improved,and the stability of the moment when the cover is opened and when it is in place is guaranteed effectively.