The strong deformation and reactivation of large- scale ancient landslides is increasing and becoming more frequent in recent years causing disasters and serious losses. The factors influencing development and deformation of ancient landslides are very complex and difficult to identify. In this study, the Small Baseline Subset Interferometric Synthetic Aperture Radar method, referred to as SBAS- InSAR, combined with remote sensing interpretation, was used to study the surface deformation characteristics of the Xiongba ancient landslide located on the west bank of the Jinsha River from October 2017 to June 2020. The research results indicated that, the volume of the Xiongba ancient landslide is huge and up to 2. 6×108~6×108 m3. According to the InSAR deformation results, there are two large and strong deformation zones H1 and H2, which are located on the front edge of the ancient landslide, and the deformation levels are divided into four levels: the extreme strong deformation (-132. 1 mm/a≤VLOS< -58. 5 mm/a), strong deformation (-58. 5 mm/a≤VLOS<-20. 3 mm/a), medium deformation (-20. 3 mm/a≤VLOS<1. 8 mm/a), and low deformation zone (1. 8 mm/a≤VLOS<55. 4 mm/a). The maximum cumulative deformation in the H1 deformation zone is about 203. 8 mm, and the deformation in the H2 deformation zone is about 302. 1 mm. Under the effect of the Jinsha River erosion, especially the dual influences of the Baige landslide- dammed lake- lake broken- debris flow/flood disaster chain in October and November 2018, which is located 75 km in the upper reaches of the Jinsha River, the erosion of the Xiongba ancient landslides foot has been aggravated, further worsening the deformation rate of the Xiongba ancient landslide. The creeping rate in the H1 deformation zone is 14~16 times larger of that before the Baige landslide disaster chain that had caused the H2 zone creeping- slide, and the Xiongba ancient landslide presents a traction reactivation state as a whole. The SBAS- InSAR deformation monitoring results were verified by the field investigation. At present, there is a local collapse at the front side of the H1 deformation zone, and the horizontal and vertical cracks in the sliding body are well developed, and there are some places in tension state. The Xiongba ancient landslide is currently a continuous creeping slide, and the deformation rates are accelerating in some parts, which could cause a large- scale reactivation of the Xiongba ancient landslide- dammed Jinsha River i.e., dam broken- debris flow disaster chain. The combined research and monitoring method of integration of space, sky and field investigation of the Xiongba ancient landslide should be strengthened, in order to provide early warning, technical support and scientific basis for major projects planned and constructed in the area, as well as for the river basin geological safety risks prevention.