In order to solve the complicated problem of working platform tilt in the case of offshore operation,aerial work and mobile equipment,a hydraulic automatic balance control system based on PLC was designed.The system was based on FX3U series PLC,Mitsubishi GS2107WTBD humanmachine interface,inclination sensor and hydraulic pumping station.Through ModbusRTU communication between the tilt sensor and PLC,automatic balance of the working surface was realized which was controlled by PLC.Experimental results show that the system can quickly and accurately realize automatic leveling.