Landslide is one of the most serious and widespread disasters in natural disasters, which seriously endangers the lives and property of residents. Based on the occurrence mechanism of landslide, this paper uses the analytic hierarchy process-comprehensive index (AHP-CI) model and takes Yuan'an County in China as an example to study and evaluate the susceptibility characteristics of landslides in this area. The geological conditions in Yuan' an County are complex, and the landslide is extremely serious. This paper will discuss separately from the inherent factors and the inducing factors that lead to the occurrence of landslides. Combined with the geological environment conditions of Yuan' an County, 5 inherent factors, including the slope, slope structure, rock and soil characteristics, geological structure, and the lithology were selected as evaluation indexes in this evaluation. Based on the spatial superposition function of GIS, the landslide susceptibility in Yuan' an county was evaluated and zoned. And in the chapter of analysis and discussion, the influence mechanism of two induced factors of rainfall and human activities on the occurrence of landslide was discussed. Since the inherent factors could not be easily changed, but the induced factors could be controlled artificially, so according to the evaluation results, scientific prevention and control measures could be put forward for different grades of landslide prone areas in the study area. This paper studied the evaluation of landslide susceptibility based on the occurrence mechanism of landslide, which has good practicability and can provide important reference for the evaluation and prevention of landslide susceptibility in other areas.