To the issue that relevant theory of setting wide construction joints for the bottom plate of the lock head in China’s ship lock regulations is not specified,this paper investigates a case of the ship lock project in Zhejiang province.ANSYS finite element software is used to numerically analyze two structural models with and without construction wide joints.The aim is to explore the influence of the position and jointing time of wide construction joints on the stress of the bottom plate.The research results indicate that the negative bending moment of the bottom plate decreases as the position of the wide joint changes from both sides towards the middle of the bottom plate,and decreases with the delay of joint time.In the design,it is necessary to consider factors such as construction convenience,and try to make the wide joint close to the middle axis of the bottom plate as much as possible.The joint should be selected when the side pier completes 60% to 80% of the total settlement to reduce the bending moment and achieve maximum comprehensive benefits.This research provides valuable reference for the theoretical study of wide construction joints in bottom plate,and helps to standardize design and construction practice.