Restricted by the existing structures of the first-line ship lock,bridges,sluice,water transfer pump station and banks,the general layout of second-line ship lock of Wannian navigation junction of Beijing-Hangzhou Canal is complex.The lock positions are compared in combination with the restrictions of existing buildings,navigation conditions,safety and operation of adjacent buildings,operation and management,coordination and aesthetics,construction conditions and investment,and the optimal lock position is determined.According to the actual situation of the design vessel type and the conditions of the approach channel of the first-line lock,innovative schemes such as flexible mooring area and common berthing pier are adopted in the layout of the approach channel.It may serve as reference for the layout of multi-line lock in the concentrated area of buildings.