Abstract: Using the flood control system in the middle and lower reaches of the Yangtze River as study objects,a numerical model for real-time flood forecasting in the reaches is presented.The model is a further development of the flow and bed load transport module that is part of a complex flood control system and able to provide information for flood control planning.To accommodate the needs of quickly and accurately forecasting floods and operating control structures in real tmie,we propose an iterative scrolling algo rithm and calibration techniques based on hydrodynamics.Coupling the numerical model with real-tmie calibration of hydrological parameters can thus be achieved.A trialoperation of the numerical model is conducted during the Yangtze River flooding seasons.The result shows that the numerical model is able to effectively address key issues that arise from executing the realt mie calibration of hydrological parameters and from realtmie flood forecasting after Yangtze Riverem bankment breached.The result provides the technical support for flood control planning and real-tmie flood operations.Our results have been used in flood operations for the middle and lower reaches of the Yangtze River.