Abstract: Failure of bench slope is the main type of mine slope failure.The bench slope′s stability is influenced by the distribution and occurrence of structures，even its failure scale has a great relationship with geometrical characteristics of bench slope.The analysis of geometrical characteristics of rocky bench slope showed that the maximum width of bench slope is the decisive factor for determining the scale of slope failure.The slope toe with maximum width is largest control point which determines to the boundary conditions of different damage scales.And the boundary conditions of damage scale in the condition of different bench slope were obtained.Compared with the traditional method used to qualitatively analyze the bench slope，the modified method can get the failure types of slopes，and acquire the damage scale of each failure type as well.It is very convenient to find out the main structure or structures′ combination of bench slope.Further analysis and calculation is made to provide the qualitative assessment of the influence area of slope failure according to the possible damage scale of slope failure and provides accurate target for calculation of stability coefficient.The modified method improves the efficiency in analysis and calculation of rocky slope stability，and provides guidance and basis for safe production in mine.

Key words: Damage scale, Geometrical characteristics of slope, Bench slope, Mine safety