Aiming at the problem of overhaul and reinforcement of working gates which are frequently used in ship lock,relying on the overhaul project of Sanbao first ship lock in Hangzhou,we carry out prototype testing and evaluation,and establish a numerical analysis model of working gates by using finite element software ANSYS.Based on the combination of water levels under different working conditions,we obtain a reasonable reinforcement scheme of working gates.The results show that the stress of the strengthened main beam satisfies the allowable stress requirement of the material.The strength,stiffness and stability of the plane lifting gate can satify the requirements under the combined working condition of water level.The calculation results can provide references for the similar projects.