Abstract: Using the flood control system in the middle and lower reaches of the Yangtze River as study objects,a numerical model for the smiulation of flow sedmient transportrates in the rivers and lakes of the reaches is presented.The model is a further development of the numerical flood module that is part of a com plex flood control system and able to provide information for flood control planning.The model is used to studying the control of flow sed mient trans portrates in the rivers and lakes of the reaches under different planning requirements.The numerical study on the in teraction between rivers and lakes is carried.As a result,the evolution trend in the riverlake relationship can thus be established.A miing at the regmie of flow sedmient transport in the rivers and lakes of the reaches,the focus is on the numerical smiulation of river scouring in the Jing Jiang river reach,flow sedmient transport rates in Jing Jiang three estuary,and sedmien tation in the Dongting Lake,as well as the coupling of rivers and lakes.On that basis,the numerical model is miproved to ensure that the numerical treatment of the model is more feasible.The result shows that the modified model is able to effectively smiulate the evolution of flowsed mient transport rates in the rivers and lakes of the reaches.Our results have been used in the planning of flood control projects and flood management practices in the middle reaches of the Yangtze River.