Abstract: In order to forecast and analyze the water regime of the basins without hydrologic stations, the "20230521" rainstorm flood in the Wujiang River Basin of Yueyang City, Hunan Province is taken as an example, and the parameters of the Xin'an River model are calibrated based on the results of the basin design flood process calculated through the field flood survey and the rainstorm calculation manual in Hunan Province. The Xin'anjiang model can be used for water situation forecasting and analysis in areas without data. The forecast results are expected to provide timely and accurate hydrological data for future flood control decisions, fill the gap in hydrological forecasting and flood development trend analysis in areas without stations, and provide technical support for flood control and disaster reduction scheduling in downstream areas, as well as reducing disaster losses.