According to the criterion of gravity similarity,we study the navigation safety of the gate area of a low water head hydropower project in a wide shallow riverway by using the overall model with a scale of 1:100.We use the ADV velocity measurement system to measure the flow velocity,control the flow rate by a standard water weir,and adjust the water level of the model by a differential tail gate.Because of the layout of the river terrain and the hydropower project,the flow velocity in the entrance area of the upstream channel is too large and the downstream forms a large range reflux.In the experiment,discharge velocity is reduced,and the overall water flow in the river is improved by the measures,such as expanding the dredging area,removing two downstream islands and increasing sluice gates.The navigation flow condition of the up and downstream channel and its entrance area of the ship lock are greatly improved by prolonging the navigation wall,changing the water permeability of the navigation wall and optimizing the topography of the channel area,which can ensure the safety of the ship.