The invention relates to a composite hydrodynamic reservoir bank slope stability prediction method, which belongs to the technical field of slope stability evaluation and landslide disaster monitoringand early warning. The method comprises the following steps of preliminary investigation of a reservoir-type landslide, selection of a displacement monitoring point, arrangement and installation of monitoring equipment, processing of monitored data, determination of landslide basic physical and mechanical property parameters and a slope slicing method, determination of overall residual downward thrust increment of the slope above a water line under effects of rainfall, determination of a slope saturation line during a reservoir water line decreasing process, determination of residual downwardthrust increment of the slope in a water line change range under effects of the reservoir water line, determination of reservoir-type landslide composite water loading and response parameters, determination of a composite hydrodynamic increased load displacement response ratio prediction model, and evaluation and monitoring and early warning of the composite hydrodynamic slope stability. The corresponding relationship between the reservoir-type landslide composite hydrodynamic increased load displacement response ratio parameters and the landslide stability is disclosed, and on the basis, a reservoir-type slope stability evolution law is analyzed and evaluated.