Abstract: In open-pit mines,stable slope is great important,and it can insure smooth mining with safety.Through the analysis of instability factors to the wedge in southwest side-slope of Shangyu stope in Fengjiayu iron mine,reinforcement and protective measures were adopted to it for the factors.Following,the wedge's displacements are monitored by measuring.The wedge's stability is expounded from theory and practice two aspects in the paper.The reinforced measures to the wedge in Fengjiayu iron mine slope are successful.And it has been proved by fact in many years.The experience can be a reference for similar mines.