Abstract: Shallow landslides in karst mountain areas are characterized by the poor development rule, small early signs, and small deformation, etc. Early identification for this kind of landslides is difficult and it is also difficult to achieve a comprehensive survey and monitoring. Examination of the formation mechanism is of important significance and can provide theoretical support for the early identification and prevention of landslides. On July 1, 2016, a landslide occurred in the Jinxing Group in Dafang County of Guizhou Province, killing 23 people. The average thickness of the landslide mass is only 4 m, and the total amount is about 9.5×104 m3. The landslide belongs to a typical bedrock landslide in karst mountain areas. The research results show that the slope angle larger than the dip angle of the bedding slope structure is the main internal factors of the landslide. The landslide occurred before the rainfall infiltration and there was no effective excretion pathway, resulting in thin layers of mudstone in slope, which directly triggered the occurrence of the landslide.