In view of the complex construction technology for maintenance of ship lock gate,the synchronous lifting device of mechanical hydraulic interlock was designed,whose structure principle and force status of the device were analyzed.The theoretical strength of the main load-bearing parts of the device,the screw piston rod and the safety tooth nut,were checked by the method of analytical calculation and finite element analysis,and the device was analyzed under the limit condition of the load falling by gravity based on the Ansys software.The results showed that theoretical strength of the device could meet the requirements,and the maximum equivalent stress in local area of the finite element analysis was close to the material yield limit.Combined with the analysis results and the structural characteristics of the device,the improvement suggestions were put forward to further optimize the design of the device.