The main purpose of this study was to forecast the inflow to Hongze Lake using the Xin’anjiang rainfall-runoff model.The upper area of Hongze Lake in the Huaihe Basin was divided into 23 sub-basins,including the surface of Hongze Lake.The influence of reservoirs and gates on flood forecasting was considered in a practical and simple way.With a one-day time step,the linear and non-linear Muskingum method was used for channel flood routing,and the least-square regression model was used for real-time correction in flood forecasting.Representative historical data were collected for the model calibration.The hydrological model parameters for each sub-basin were calibrated individually,so the parameters of the Xin’anjiang model were different for different sub-basins.This flood forecasting system was used in the real-time simulation of the large flood in 2005 and the results are satisfactory when compared with measured data from the flood. The main purpose of this study was to forecast the inflow to Hongze Lake using the Xin’anjiang rainfall-runoff model. The upper area of ​​Hongze Lake in the Huaihe Basin was divided into 23 sub-basins, including the surface of Hongze Lake. influence of reservoirs and gates on flood forecasting was considered in a practical and simple way. W a a-day time step, the linear and non-linear Muskingum method was used for channel flood routing, and the least-square regression model was used for real-time correction in flood forecasting.Representative historical data were collected for the model calibration.The hydrological model parameters for each sub-basin were calibrated individually, so the parameters of the Xin’anjiang model were different for different sub-basins.This flood forecasting system was used in the real-time simulation of the large flood in 2005 and the results are satisfactory when compared with measured data from the flood.