A three-dimensional hydrodynamic numerical model was used to study the hydrodynamic characteristics of the excavated basin built in the convex side of a bend river and the influence of the project on the river. The results showed the project’s influence on the water level and velocity distribution of the river section. It showed that after the wharf built, the backwater in the main channel occurred mainly in the narrow river before the bend end, indicating that the narrowed section of a meandering channel had great influence on the backwater. The range of the water level and velocity near the wharf apron was larger than other regions, perhaps resulting in scouring in this area. The wharf construction influenced the bend exit more than the entrance and middle. In the wharf working condition, there was obvious backflow in the basin, while the velocity was small. It may cause the depositing that will obstruct the wharf operating. The results were useful for studying the hydrodynamic characteristics of excavated harbor basins and its influence on flood control in the meandering river. The results could also provide the basis for the wharf management.