Abstract: From August 25 to 26, 2021, a continuous regional rainstorm occurred in Xiaojin county. Based on several numerical model forecasts, this paper tests and analyzes the rainfall area, magnitude and main precipitation period of this rainstorm. The results show that: Affected by the southward movement of high-altitude cold air and the eastward movement of plateau lifting trough, the South Asia HIgh was stable, under the combined action of water vapor conditions, thermal conditions and dynamic conditions, a regional rainstorm occurred. According to the test results of various prediction models, EC model can more accurately predict the precipitation magnitude of the rainstorm, and GRAPES_GFS model has guiding significance for the prediction of regional rainstorm, while SWC model excels in predicting the rainfall area of small-scale rainstorm. GRAPES_3km model and Guangzhou model can predict the rainfall area and precipitation magnitude more accurately in short-range forecast.