Abstract: Boligou landslide located on the left bank of Boligou of Xuejiawan town, is a traction type landslide composed of landfill soil. Since several treatment measures had failed from 2009 to 2012,the investigations and regulation project for the landslide have to carry on again. This paper analyze the slope structures and deformation mechanism of the Boligou landslide through further exploration research：congenital condition for landslide formation is the natural slope shape changed by man-made; material basis for landslide deformation is special slope structure; inducing factors of landslide deformation are infiltration of surface water, the groundwater, and riverbed silt uplift and landslide slope toe excavation intensified deformation. On the basis of accurate analysis of landslide deformation mechanism, put forward engineering treatment measures and achieved success. At the same time, this paper analyzes the reason for the multiple treatment failure, and the root cause is paying less attention to the engineering geological investigation which leads to insufficient understanding of the deformation mechanism of landslide, especially erroneous judgement to the buried depth of the slip plane and ignoring the effect of groundwater on landslide. Under the condition of insufficient understanding of landslide deformation mechanism, blind implement the anti-sliding engineering resulted in multiple treatment measures failure. Therefore the important premise of radical cure landslide is to find out the engineering geological condition and landslide slope structure, and accurate analysis of the deformation mechanism and development process of the landslide by taking necessary means of engineering geological investigation.