Abstract: Changzhou locks No.3 and No.4 will be the biggest locks in China in terms of lock plan dimensions.They are designed to be interconnected twin locks and adjacent to locks No.1 and No.2.The layout of locks No.3 and No.4 is limited by the bridges upstream and downstream of the lock,the normal operation of locks No.1 and No.2 during the new locks construction,and local residents and industrial facilities.So the layout of newly built locks will be the key factor for investment and operational conditions.The factors which influence the layout of locks No.3 and No.4 are analyzed in the paper.The possible schemes of layout are studied.The recommended scheme is put forward with general requirements of lock layout and the special requirements of Changzhou locks No.3 and No.4.