The eastern margin of the QinghaiTibet Plateau is the region with greatest topographic steepness, strongest internal and external dynamic forces, and extremely frequent climate change. The complex geological evolution process has made the region the most concentrated distribution and the most dangerous area of revival of the ancient landslides. Based on field investigation, drilling and geophysical exploration, InSAR monitoring, laboratory tests and numerical simulation analysis, this study analyzed the development characteristics, formation and evolution process and revival factors of the Garazong ancient landslide in Xianshuihe fault zone of western Sichuan. The results show that (1) The Garazong ancient landslide was formed in the late Late Pleistocene, about 42~30 ka years ago, with a volume of 3150×104 m 3, and belongs to a giant ancient landslide. (2) The Xianshuihe fault activity is the main controlling factor for the formation of Garazong ancient landslide. The cracking effect of previous strong earthquakes may result in the formation of ancient landslide and subsequent fault creeping further causes the cracking of the slopes, which increases the infiltration of atmospheric precipitation, and further expands the cracks. (3) SBAS- InSAR monitoring and numerical simulation results show that the overall stability of the landslide is good at present. But cracks, steep slopes and collapses in different degrees occur in many parts, with some suffering strong deformation, which can produce largescale revival slides due to strong earthquakes and extreme rainfall conditions. It is suggested that drainage and antiskid measures should be strengthened.