The Guichi waterway in the lower reaches of the Yangtze River is a three-branch river section.After the implementation of the Anqing Phase II project,the goal of maintaining a water depth of 6 meters was achieved.However,there are still problems such as insufficient restrictions in the north port,weak hydrodynamics in the middle and north ports,and insufficient water depth of 8 meters at the entrance and exit of the main channel between the two ports.Therefore,a combined approach of theoretical analysis and physical model experiments is adopted,based on the concept of restricting the development of the northern port,increasing the diversion ratio of the middle port,and regulating the flow velocity in the shallow area,the engineering effects of different schemes were compared and analyzed through model experiments,and a preliminary regulation scheme is proposed.After the implementation of the project,the goal of stabilizing the waterway of the middle port,increasing the hydrodynamic and shallow scouring effects of the main waterway can be achieved.After the implementation of the combination plan,the maximum increase in the diversion ratio under the regulation flow is about 3%,and the maximum increase in shallow flow velocity at the inlet of the middle port is about 0.20 m/s.