Research conclusions: ( 1) Deformation failure mode of the slope is dependent on the inner structure of slope，the physic － mechanical properties and outsider factors; ( 2) Studies on mechanism of the slope deformation failure and on slope deformation failure and stability at every different evolution stage are necessary for proposing proper slope treatment measures in accordance with its development stage; ( 3) Comprehensive treatment proposition，which combines several propositions such as earthwork reliving，materials replacement，anchorage，retaining and drainage etc． ，could be taken into consideration during the treatment．