Abstract: The displacement of colluvial landslide in reservoir area is affected by the compound dynamics of the circulating fluctuation reservoir water level and rainfall. This paper is based on the systematic analysis of the change law of reservoir water level, rainfall and displacements of reservoir landslide. It proposes and determines the calculation method for the conversion coefficient k of rainfall and reservoir water dynamics. Through the conversion coefficient(k), the paper organically couples and superimposes the two different hydrodynamic loading effects of rainfall dynamics and reservoir water dynamics, and establishes the calculation method of compound hydrodynamic loading parameters. Then, the paper takes the compound hydrodynamic change and its displacement change as the dynamic loading parameters and its response parameters respectively, and establishes the physical prediction parameter and model of the displacement response ratio with dynamics increment for the reservoir landslide. At the same time, the paper studies the model to the systematic analysis and evaluation of the stability evolution of Baishuihe landslide under the compound hydrodynamic action. The results show that the change law of the compound hydrodynamic displacement response ratio with dynamics increment for the landslide is consistent with the dynamic evolution law of the stability. It is shown that the compound hydrodynamic displacement response ratio with dynamics increment is an effective physical evaluation parameter of reservoir landslide. The stability of this kind of landslide can be analyzed and evaluated by using this physical evaluation parameter and prediction model.