A synchronization circuit in a deep sea pressurization system was taken as the research object, aiming at the displacement accuracy control problem of the synchronization circuit under external interference forces, the physical model of the synchronization circuit was established by using the hydraulic library in AMESim, and the PID controller was established by using Simulink, and then the co-simulation was carried out to observe the control performance of the synchronization loop under external interference forces. The results shows that the displacement accuracy of the PID-controlled synchronous loop can meet the design requirements.