Abstract:As the mining depth increases, the stability of the open-pit mine slope is gradually decreasing, which has a serious impact on mine safety. In this regard, there is currently no accurate evaluation method. In this paper, five influencing factors including slope rock cohesion, rock internal friction angle, atmospheric annual precipitation, slope height, and slope angle were used as evaluation indicators. Coefficient of Variation (CV), G1 method, multiplication combination, and mixed cross combination were used. Four methods were used to determine the weight, and then the matter-element extension method was introduced to analyze the stability of 13 types of open-pit mine slopes at home and abroad, and compared the accuracy of the four weighting methods. The results show that the cohesion of the rock formation and the internal friction angle of the rock have a greater impact on the stability of the slope, and the weight results obtained by the improved hybrid cross weighting method are more reasonable. The hybrid cross-weighting-extension theory is applied to the open-pit slope stability evaluation of the Chang''an gold mine in Yunnan. The results obtained are consistent with the field measurements and obtained obvious effect.