On the basis of systematic analysis of the material composition and destabilized mechanism of debris landslide induced by water，the dynamic action of unloading and loading and its response law of groundwater in the process of the dynamic stability evolution of the slope are systematically analyzed. The unloading-loading response ratio parameter to evaluate the laws of the dynamic stability of the landslide evolution and destabilized features are analyzed and put forward from the viewpoint of the nonlinear system dynamics. This paper firstly proposes that the monthly change of groundwater table can be taken as the unloading- loading parameter of debris landslide and its displacement velocity and acceleration rate can be taken as the response parameter to unloading-loading are proposed. Thus, the dynamic displacement parameters and dynamic prediction model of the unloading-loading response ratio of the groundwater table are determined. Meanwhile, the quantitative relationship between unloading-loading response ratio and damage variable & the stability coefficient and the criterion of displacement response ratio to unloading-loading are determined by using the theory of damage mechanics and the damage variable parameters of slope. Finally, taking the typical debris landslide of the Three Gorges Reservoir region—Xintan landslide for example, the calculation of unloading-loading response ratio of monitoring points of Xintan landslide is completed by using the dynamic displacement prediction models of the groundwater. The computed results show that the curves of unloading-loading response ratio of monitoring points basically agree with the dynamic evolution law of the slope stability. The results of the study show that the parameter proposed in this paper is a kind of effective dynamics appraisal parameter of displacement in the stability of landslides induced by water and it can be used to make real-time monitoring warning and evaluation on the dynamic stability of this kind of landslides.