[Objective] The formation conditions and spatial-temporal evolution of chair shaped soil landslide in the Three Gorges reservoir region were studied in order to provide the theoretical support for landslide monitoring and warning.[Methods] Taking Baijiabao and Bazimen landslides, the typical chair shaped soil landslide in the Three Gorges Reservoir area as examples, the formation conditions of these landslides were analyzed and compared with typical landslides in the Three Gorges Reservoir area. The spatial and temporal evolution of the landslides were analyzed based on the topographic and geomorphic characteristics of Xiangxi river basin.[Results] The formation conditions of chair shaped soil landslides were obviously different from other typical landslides in the Three Gorges reservoir region, and the formation of such landslides in Xiangxi river basin was obviously affected by valley topography.[Conclusion] The formation of chair shaped soil landslide is influenced by factors such as lithological conditions, sliding surface morphology and stratigraphic state. The chair shaped soil landslide in Xiangxi river basin is gradually formed with the evolution of the valley.