Flood submergence scenario is affected by many factors such as flood discharge in the area, change of riverbed topography change and operation schedule of channel projects. The determination of flood scenario is a precondition for carrying out research on river and beach area management, as well as flood control design and beach area positioning function. In view of this, a two-dimensional flood evolution model is established by using the Delft3D Hydrodynamic model to simulate the flood submergence process in Canghai Wetland Park as a case study. The model is verified by historical data of 20-year flood and the results were reasonable. The flood routing process in Canghai Wetland Park encountering 50-year flood is simulated, and the characteristic hydraulic factors such as flooded area, maximum submerged area, and water level change process are obtained. The research achievements provide a theoretical reference for flood control planning and real-time flood forecasting in the area and offer reliable parameters for water quality improvement projects in the flood area.