Abstract: For the tidal river with navigation requirements, the combined use of sluice and pump will extend the drainage time of inner river and increase the drainage flow, which will lead to the increasing velocity of horizontal flow discharged from inner river into the outer river and affect the navigation. Taking the Baihuatou water conservancy project in Zhongshun polder as an example, the influence of inner river drainage on the navigation was analyzed by physical model test, and the flow adjustment measures suitable for different working conditions of rising tide, falling tide and turning tide were put forward. According to the experimental results, two rows of diversion piers at the intersection of the inner river and outer river were set. The first row of diversion pier near the inner river is to divide the water flow from the inner river into several strands. The second row intersects with the first row with 45 degrees, which can disperse the scattered water flow and achieve the purpose of deceleration by multiple flow collision. The flow adjustment technology is universal and can be applied to similar engineering river reaches, which is of great significance to promoting the development of navigation industry in the Pearl River Delta.