Abstract: According to the actual flood prevention needs of Hunan province, the small and medium river basins of Hunan province were divided into five major basins （Xiangjiang River, Zishui River, Yuanjiang River, Lishui River and Dongting Lake） using the natural watershed method. Based on the water levels of 27 hydrological stations and the precipitation products of the 97 meteorological stations and grids from 2008 to 2018, the relationship between heavy precipitation and floods were further studied. Thus a water level forecasting model based on river basin precipitation was established to predict whether there would be floods. The forecasting model was tested using the example of heavy precipitation and flood process from July 6^th to 13^th of 2019. Results showed that during this flood process, the forecasting peak value and changing trend of the water level were consistent with the actual water level. Therefore, the model has good effects on water level forecasting.

Key words: small and medium rivers, floods, forecasting model, Hunan province