For quantitatively assessing risk management of a slope under earthquake impact, quantitative analysis was studied by choosing factors of slope risk management. For two scenarios, objects just under the slop and objects have a distance to the slop. Especially, sliding distance and its incidence during one earthquake were calculated. Then the factors of probability for the slope reaching the objects were quantitatively assessed. The results can provide not only theoretical foundation for quantitative analysis for risk management of a slope under earthquake impact, but reference for the process from a qualitative evaluation to a quantitative assessment for risk management.