Abstract: Aiming at the problem of open－pit slope stability controlled by the discontinuity under blasting influence，the working bench slopes of a limestone mine was taken as the research object，and based on the statistical analysis of preferred discontinuity in the study area，the qualitative and quantitative study was carried out on the stability of the working bench slope under the natural condition and blasting influence by using the discrete element software 3DEC．The results can provide reference for the mine design and safe production．