Based on specific research condition for the water depth and locking mechanism of the Three Gorges ship lift chamber,we analyze the force variation of pinion gear and the influence of the water depth of the chamber on the force of the locking mechanism under the condition of single driving point pressure holding failure of the locking mechanism,and study the force characteristic and action rule under different conditions,check the influence of ship lift chamber inclination on the force on locking mechanism by mathematical equation,and obtain the qualitative and quantitative variation rule of the force on the pinion gear under this research condition theoretically.The results show that the pressure maintenance failure of locking mechanism can cause the force change of the driving mechanism for chamber.The influence of ship chamber inclination on the allowable unbalance loading water depth of locking mechanism is small.