Aiming at key issues including restricted river turning radius and excessive flow velocity in the approach channel of reconstructed and expanded ship locks connected to sharply curved rivers at the downstream,physical model and ship model tests are conducted to systematically study the layout of the lower approach channel and navigable flow conditions of such ship locks in sharply curved river reaches.The results show that a ffected by both the high-velocity discharge from the hub and the boundary of the sharply curved river,water flows directly towards the concave bank of the bend and then flows back to the lower approach channel and its entrance area on the convex bank,making the navigable flow conditions of the lower approach channel and entrance area in the designed scheme fail to meet specification requirements.Through comprehensive measures such as adjusting the layout of the mooring section and the ship lock,regulating the convex bank line,dredging the concave riverbed and adding separation walls,the areas with excessive transverse flow velocity in the lower approach channel and entrance area of the final scheme are greatly reduced.Ship model tests verify that vessels can smoothly pass through the lower approach channel and its entrance area to access the ship lock when the discharge Q≤5,000 m3/s.The research results can provide technical support and reference for the design and implementation of mountainous ship lock reconstruction and expansion projects.