Abstract: According to the characteristics of the geological disasters in the Three Gorges Reservoir of landslide, and taking Tanjiahe landslide in Reservoir for example, deformation characteristics and monitoring data of landslide are obtained through field geological survey. Combined with the engineering geological conditions of the landslide, reservoir level and rainfall, the two major factors influencing the landslide deformation are analyzed. Tanjiahe landslide is located on the right bank of the Yangtze River, and its deformation is more obvious since the Three Gorges Dam reservoir impounded, so the study of the relationship between Tanjiahe landslide deformation and reservoir level and rainfall and other predisposing factors is very necessary. Studies have shown that Tanjiahe landslide in the initial deformation stage, and the central and trailing edge deformed faster, showing a gradual passage landslide. The deformation of Tanjiahe landslide is more significant in the reservoir level and rainfall additive effect, reservoir water will soften the soil, resulting in uplift; and the rainfall will reduce the stabilizing force of slip zone, increase the total weight of the sliding body, increase the decline in power and forme of hydrostatic pressure. Especially when the reservoir level rises, landslide deformation rate show a sudden increases. Tanjiahe landslide is considered reservoir level elevation type slope. In this paper, combined with the Three Gorges Reservoir water level's changes and rainfall, the relationship between landslide deformation and the both factors is quantitatively analyzed, reasonablily, provide the basis for future landslide monitoring and warning.