Abstract: In order to clarify the influence of extended deep mining of surface mine on goaf, high and steep slope and surface, the mining area of Laohutai Mine was taken as the background. By using MIDAS GTS-NX software, the slope deformation and failure range induced by continuous extended deep mining of E5800 section in Laohutai Mine was analyzed by numerical model. The mechanism of slope slip induced by extended deep mining of surface mine was revealed. The results show that with the deepening of open-pit mining, the position changes of maximum horizontal displacement and maximum settlement on the surface of slope gradually decrease. Compared with the position of the maximum subsidence point of the first mining, the fourth mining moved 13 m to the north, and the subsidence value increases by 57.5%. Moreover, with the increase of the open pit and the decrease of lateral constraint, the stress of the rock mass of the slope gradually moves to the pit, which indicates that the influence of the activation induced by the mining of surface mine in the underground mining area on the stability of the slope gradually increases. Considering the influence of blasting factor in the mining process, the most dangerous section N900 is selected to evaluate the slope stability, and the corresponding monitoring means are put forward in view of the possible dangerous situation.