In this paper, the 2020 Aniangzhai Landslide in Danba County in Sichuan province, China was investigated by using multi-temporal SAR and optical datasets. The pre- and post- failure scars of the landslide and debris flow were depicted using high-resolution optical images from the Planetscope satellites. The descending Sentinel-1A/B C-band SAR images were applied to explore the deformation characterization of this event. Advanced time-series InSAR analysis was processed to detect the sliding motion, with identifying the spatial-temporal pattern and evolution of the failure area of the Aniangzhai landslide. The maximum line-of-sight (LOS) deformation rate measured over the slope surface was up to -80 mm/year. Time series analysis of selected measurement points indicates that the cumulative deformation peaked at -113 mm. Most importantly, two significant accelerations were detected at the upper area of the Aningzhai slope before the occurrence of failure. By comparing the time series analysis of points in different sections, it is evidenced that the initial failure of lower part triggered the sliding motion of upper part at the slope.