The water flow outside the ship lock is greatly affected by the unstable flow discharged from the hub.To address the adverse effects of flow velocity and flow patterns on ship navigation and maintain the flow conditions of the approach channel,this article analyzes the causes of unstable water flow in the downstream approach channel,combined with the layout and structural types of the diaphragm wall built in recent years.Through methods such as plane layout,model testing,and data statistical analysis,the impact of various structural forms such as solid wall,barrier pier and permeable hole walls on water flow conditions has been explored.Multiple types of approach channel flow separation wall structural arrangements and optimization measures are proposed.