In order to control the oil film thickness on the upper and lower oil cushions of asymmetric hydrostatic bearing anti-eccentric load horizontal heavy-duty servo cylinder under the condition of constant pressure oil supply,the transfer function of the oil film thickness on the upper and lower oil cushions was deduced by establishing the flow continuity equation of the servo cylinder and the dynamic equation of the piston rod. The position servo synchronous control system was designed, the coupling relationship of the control system was decoupled, and the stability was analyzed by the second method of Lyapunov.The simulation model of the control system was built through MATLAB/Simulink，and the system was simulated by inputting sinusoidal, step and random load signals. The results show that the control system has the fastest synchronization performance and the best reliability and stability under the interference of random signals,which can realize the precise control of the oil film thickness,ensures that the piston rod is aligned at all times during the operation of the servo cylinder,improve the sealing performance of the servo cylinder, and overcome the adverse effect caused by the unbalanced load.