The Three Gorges lock is a five-step lock with a higher water head. Since the two adjacentlined locks and the ship lift share the downstream approach channel, the hydraulic problem of the lock became the most difficult among the world’s existed locks, and is one of the key problems of lock design. Based on the scientific research results, with the rational arrangement of the water-carriage system and optimization of operating parameter of the valve, we overcame the problems of waiting ships in the first lock in the four-run mode, and realized the working condition with the head rising from 45.2 m to 47 m. Thus the five-run mode was transformed to four-run mode, and the lock capacity was effectively improved.