Abstract: At 18:55 on January 3^rd, 2022, a bedding landslide disaster occurred in Guihua street, Jinhaihu newly liberated area, Bijie City, Guizhou Province, with a volume of about 3.5×10⁴ m³,which resulted in 14 deaths and 3 injuries. Through the detailed geological survey, this paper comprehensively uses UAV aerial photography, field testing and other technical methods to describe the characteristics of Tianwanzi landslide in detail, preliminarily analyze the movement process and genetic mechanism of the landslide, monitor and analyze the potential risk of the landslide residue, and put forward search and rescue suggestions for on-site rescue operations. The preliminary research results show that the special topographic and geomorphic conditions in the landslide source area, weathered and fragmented argillaceous dolomite and unfavorable rock mass structural plane are the internal causes of the landslide, and the change of surface morphology and stress distribution of the slope caused by slope excavation disturbance is the external cause. Before the occurrence of Tianwanzi landslide, there was no obvious sign of slope deformation, and the disaster occurred suddenly, resulting in great human and economic losses. In-depth study of the formation process and disaster mechanism of Tianwanzi landslide has practical guiding significance for the prevention and control of potential geological hazards with similar conditions in Guizhou mountainous area.