Abstract: This hydrodynamic model is founded by S.Q.Wang for predicting the fluvial processes in the reservoirs and the river channel.The new formulas of flow resistance and sedimentt ransport are used in the model and the characteristics of hyperconcentration and nonuniformity of sediment are considered in the model.This model is verified by using observed data from 1960 to 1988 in the Sanmenxia Reservoir and the lower Yellow River.It is successfully applied to predict the processes of aggradation and degradation of the Xiaolangdi Reservoir and the lower Yellow River for various schemes.