Xiajiang hydro-junction is located at the upstream of Baqiu town in Xiajiang county,Ganjiang river’s midstream. It’s difficult to put the approaching channel of shiplock at such a slightly curved reach when the shiplock is on the left side.There are many factors influencing the flow conditions of the approach channel and entrance area,such as the baffle wall,topographical condition of site,etc.The lock chamber was originally designed as a separated structure which is commonly used,but it must be changed when there is a large-scale faults.Some methods are adopted to make the navigation flow conditions better,and the integral structure is used in the lock chamber by finite element analysis.