It is often necessary to excavate a deep foundation pit near the existing ship lock for the expansion of lock capacity，which may cause excessive additional displacement of the adjacent existing lock，and then affect the lock safety and normal operation. To study the multi-factor sensitivity of the newly built foundation pit to the adjacent ship lock，four main factors including the strut levels，the thickness of the diaphragm wall，the row spacing of diaphragm walls，and the distance between the excavation and the ship lock were selected to design 3 levels orthogonal test，based on which series of finite element models were established. The horizontal and vertical displacement of the ship lock was adopted as the evaluation indexes，and the above four factors were analyzed and ranked through range analysis. The results show that among the four factors，the distance between the foundation pit and the ship lock has the most significant influence，strut levels take second place，and the influence of diaphragm wall thickness and row spacing is relatively weak. The influence law of diaphragm wall row spacing on ship lock displacement is different from other factors. The trend of ship lock displacement changing with diaphragm wall row spacing is not monotonous，which is different from that of other factors，but there is an optimal value. Within the current factor level range，optimum results can be obtained when the row spacing of diaphragm walls takes the intermediate value of 15 m while the other three factors take the maximum values.