Abstract:Recently,the quantity and scale of underground building increase rapidly with the development of city construction,which triggers the development of technique of deep excavation and support. Because pit engineering is a complex geotechnical engineering and affected by many factors,support failure often occurs. Therefore,how to reinforce pit slope after its loss of stability,collapse and slide is a key problem which designer,builder,supervisor and manager who are engaged in pit engineering have to face. It is proved by practice that micro steel pipe piles used to reinforce failure slope is effective. This method is adaptable,safe and convenient with immediate effect and small displacement on top of piles. The principal problems of designing and making of micro steel pipe piles and the measures to solve them are put forward by analyzing the attribute of this method through a case,in which micro steel pipe piles are used to reinforce failed slope. The technique will be helpful for similar engineering.