从水力学条件论证了船闸采用4级运行方案的可行性。通过原型调试，采取中间及阐首优化后的输水方式运行，基本消除了闸室第一分流口空化，船闸在超过设计的45.2 m水头下工作条件较好，在三峡船闸完建期156 m蓄水位船闸采用4级运行方式具优越性。

This paper expounds the superiority of adopting four-step operational mode for TGP lock under impounded level 156 m in the finishing construction period, and demonstrates the feasibility of adopting four-step operational mode with the hydraulic conditions. After adopting the optimizing water conveyance pattern by means of prototype debug, the cavitation of the 1st-bifurcation at mid chamber has been basically eliminated, the working conditions of the lock under exceeding design water head 45.2 m has been confirmed well, therefore, the four-step operational mode can be adopted for TGP lock.