Abstract: Through analyzing the field data in the process of collection and arrangement of Darong landslide, failure mechanism conceptual model of Darong was established. In addition, its failure mechanism was studied through finite element method. It is concluded that the failure field in the left of slope saw a decrease in stability coefficient because of artificial landfill, as well as the change of seep conditions of groundwater. As a result, there are changes of stress field in failure field, creep in the middle-upper part of slope body and fracturing in the rear edge of slope, which caused stress concentration in toe of the slope. Finally, shear failure was happened in toe of the failure field caused by rainfall duration, which contributed to the landslide formation because of unstable failure of failure field.