Xiajiang hydro-junction is one of the control project of the Ganjiang high level navigation channel,in which the dam site locates at an “S” type sharp bend river section.The junction adopts the layout of structures concentrated with power house and ship lock at different banks.The lock is on the concave bank,and its entrance area of upstream approach channel lies on the downstream of in which the upstream bend convex of the “S” section and the entrance area of downstream approach channel lies on the downstream bend concave of the “S” section,which is neither favourable to the navigation flow condition.Meanwhile,the junction also has the characteristics of low water head and large discharge,all of above provide a complicated navigation flow condition.With the scale model experimentation of the overall junction and the self-propelled ship model experimentation(scale is 1:110),the comprehensive optimization measures have been put forward and verified,which are the along bank control for the both the upstream and downstream and bottom-open-type guide wall for the downstream,and the measures greatly improve the flow conditions in the entrance area of the upstream and downstream approach channels,and all the hydraulic characteristics satisfy the rules,the navigation safety of ship has been confirmed.