Abstract: Yunnan Province is one of the areas where landslide hazards occur frequently in our country. This paper presents a case history of landslide investigation in Weixi County in the northwest of Yunnan Province. It summarizes the formation mechanism and hazard model of landslides, which has a practical and guiding significance for promoting the landslide control in the southwest of our country. Weixi County is one of the counties in Yunnan Province for the refined investigation and the risk assessment of the geological hazards in key areas in 2020. A total of 384 landslides have been identified, and there are mainly weathering debris flow type, subsurface erosion and subsidence type, and shear erosion loading type for the formation mechanisms of landslides. The formation of a landslide may be the result of several formation mechanisms. Taking into the hazard bearing body and the landslide movement account, the main hazard models of the landslides in Weixi county include the creep rupture, the follow-up, the high-speed debris flow and the landslide debris flow chain hazard models. Analyzing the formation mechanism and the hazard models of landslides can provide guidance for the prevention and reduction of the geological landslide hazards in the county and similar areas.

Key words: Landslide, Formation Mechanism, Geological Hazard Model