Abstract: The Tangjiawan landslide occurred twice on September 5, 2016 and May 12, 2008, respectively, and blocked the Tongkou river and created a barrier lake. This landslide is of important significance as it presents a good example for the evolution of a coseismic landslide. In this paper, the volume of the Tangjiawan landslide and the barrier lake is calculated accurately by comparing pre-and post-DEMs of the landslide. The deformation evolution history of the Tangjiawan landslide is analyzed by using the multi-temporal remote sensing images. Based on the field investigation, the mechanism is also analyzed. The results show that there are three times of sliding at the study area. For the coseismic landslide, the source area of the landslide is traversed by the Yingxiu—Beichuan fault, and the oblique-thrusting of the fault apparently triggered the initial failure of the coseismic landslide. However, the revival landslide of 2016 is the result of combined geological function of inner and outer powers.