Abstract: Deformation and failure of the interbeded slope of sand and mud stones is a serious geological problem during the engineering construction. In this paper, taking the Three Gorges Reservoir Area(Changshou-Fengdu section) as an example, the slope structure, evolution process and failure characteristics are studied based on field investigation. And then the failure coefficients of the 38slopes were calculated based on the factor of topographic concave-convex degree and the SOM model. The results show that 70% of the slopes along the Three Gorges Reservoir Area(Changshou-Fengdu section) are consisted of mudstone interbeded with sandstone. There is a certain difference in the failure mechanism between the slope which consisted of mudstone interbedded with sandstone and the slope consisted of sandstone interbeded with mudstone. According to the failure mechanism and stability assessment, the failure coefficients of the 7slopes in Three Gorges Reservoir area(Changshou-Fengdu section) are bigger than 0.4,indicating comprehensive prevention methods should be adopted, especially for the slopes consisted of sandstone above and mudstone below.