Abstract: Based on two mining methods of the boundary extension method at lower part and the boundary contraction method at upper part with steep end-slope mining，and combined the law of superposition and the end-slope timeliness of open pit slope，the two local steep slope mining methods are put forward，that is，the steep slope extension at lower part and the slope contraction at upper part.Meanwhile，the stripping ratios of two methods were deduced.The controlling variates method was used to study the impact of the thickness of coal seam，the rock thickness and the height of the steep slope on the stripping ratio.The conclusion is that the steep slope extension at lower part and the slope contraction at upper part are sensitive to the change of the thickness of coal seam and the cover thickness.With the western slope in south area of Huolinhe open-pit mine as a case，the steep slope contraction method was the optimal scheme for Huolinhe open-pit mine with 56 million RMB investments saved.

Key words: Surface mine, Steep end-slope mining, Local steep slope, Stripping ratio