The process of excavating the foundation pit of adjacent ship lock supported with row-piles was simulated with finite element method. The authors investigated the displacement of the lock chamber wall and retaining piles, the regularity  in the changes of soil pressure behind the chamber wall and subgrade reaction against the excavation depth, as well as the relation between them. The study reveals that the lateral displacement can be reduced to ensure the stability of lock chamber wall by maintaining the soil pressure behind the wall when excavating the foundation pit and meanwhile avoiding an excessive difference of subgrade reactions of the chamber wall between front-toe and back-toe. The study will be helpful for engineering design and construction.