Landslides developed along the Lancang River are generally characterized by deep accumulation layers, large volume scale, and complex formation mechanisms. Once a landslide occurs, it may block the Lancang River, causing extremely serious hazards. Using surface displacement data (InSAR/GNSS), numerical simulation, etc. to analyze the deformation characteristics of landslide disasters are of great significance to landslide prevention. Taking the Zhongjinzu Landslide in Markam County of Xizang Autonomous Region as an example, the deformation characteristics and instability evolution process of the landslide based on the collaborative technology of "InSAR-GNSS-FLAC3D" was studied. The results show that the deformation of the Zhongjinzu Landslide mainly follows a cycle of "creep sliding-accelerated sliding-creep sliding", with the strong deformation at the front edge of the slope body. Under extreme working conditions such as heavy rainfall, the landslide will form a throughgoing surface of rupture and trigger disaster. The research results can provide references for the prevention and control of similar landslides.