The losses caused by flood disasters are becoming increasingly serious with the rapid development of social economy.As an important non-engineering flood protection measure,real-time flood forecasting plays an important role in flood control.Due to the severity of flood disasters and the complexity of flood routing process in the Huaihe River basin,the research on flood forecasting system has been a focus for a long period.A case study from Wangjiaba to Xiaoliuxiang section is discussed and a research on flood forecasting system is presented in this paper.On the basis of the hydrologic characteristics in the study area,this paper takes flood flow routing as mainline,uses the Xin'anjiang model for runoff yield prediction,generalizes flood diversion and retarding regions, applies hydrologic and hydraulic methods to simulate flow routing in the main channels,and fits stage-discharge relationships by multiple regression method.A general system is established by integrating the above parts and then by coupling K-Nearest Neighbor method to attach real-time correction to forecasting results for the real-time forecasting system.Inspected in 2003 and 2007,the system achieved high prediction accuracy,which proves that the system is sound and can be applied to this basin.