The basic task of flood forecasting is to predict the total amount of flood, the time of flood peak, and the process of flood occurrence based on collected real-time rainfall, evaporation, water level (flow) and other data. The development and integration of the entire system adopts C/S (Customer Server) mode, and the development of each subsystem of the system software is carried out around the network database. The main functions of the flood forecasting subsystem include data preprocessing, forecasting calculation, real-time correction, etc., providing flood forecasting information for the reservoir dispatching subsystem and the integrated information service subsystem.