Abstract: The geological environment on the eastern edge of the Qinghai−Tibet Plateau is complex. Under the combined effects of internal and external forces, this region has witnessed the development of a series of large to super−large deep−seated landslides, leading to multiple instances of landslide−induced river blockages. The Guili landslide, located in Jiangda County, Xizang, is a large−scale deep−seated landslide characterized by complex spatial structure and intense deformations. This study, based on data collection and analysis, comprehensively utilized research methods such as field geological surveys, remote sensing interpretation, unmanned aerial vehicle aerial surveys, InSAR deformation monitoring, and numerical simulation to analyze the geometric and creep deformation characteristics of the Guili landslide and elucidate its origin and instability mechanism. In the view, it can be divided into two parts: the trailing edge of the landslide area (Ⅰ) and the landslide stacking area (Ⅱ). The landslide stacking area can be further divided into a local stabilization zone (Ⅱ₁) and a strongly deformed zone at the leading edge (Ⅱ₂ and Ⅱ₃). The volume of the landslide is approximately 6.55 × 10⁷ m³, with revealed depths of the deep slip zone from drilling being 64.02 m, 57.90 m, and 54.13 m. Based on SBAS−InSAR monitoring data, the Guili landslide is currently in a stage of overall creeping deformation, with localized areas experiencing accelerated deformation. The highly deformed zone at the front edge of the Guili landslide exhibits progressive deformation and surface maximum deformation rate of up to −92.12 mm/a. Deformation of the landslide slope is primarily influenced by rainfall and river erosion. Numerical simulation results indicate that under natural conditions, the displacement and deformation of the sliding mass are relatively small, indicating good stability. However, under heavy rainfall conditions, the strong deformation zone at the leading edge of the Guili landslide shows obvious signs of deformation, and may be destabilized and sliding, pulling the back of the pile body sliding, which is a typical traction creep−slip deformation mode, and the sliding pile body may block the Jinsha River, and there is the risk of forming a disaster chain of blocking the river − dam failure − flooding. These research findings can provide valuable insights for coping with large−scale deep−seated landslide disasters and hold theoretical and practical significance for stability assessment of such landslides.