Abstract: Systematic researches on the supporting design for the breaking cavern in No.3 Mining District of Jinchuan are conducted,and some valuable achievements are obtained.At first,according to the characteristics of engineering geology and surrounding rock mass,the general computation scheme of three-step excavation,two-time supporting and three-time yield is put forward.Sixteen yielding supporting schemes are designed by the orthogonal test table of three levels and four factors.Then,the sixteen supporting schemes are computed and analyzed by use of the FLAC2D software,and the optimization appraisal index Es first put forward in the paper is applied to synthetically assess and analyze these schemes.The optimum yield scheme is got.Finally,the three-dimensional excavation and supporting computation of twenty-four working processes is implemented by use of FLAC3D for the optimum scheme,and some reasonable advices are gained.The results of practical application indicate that the optimum supporting scheme is in favor of the long-term stabilization of the deep and large-span soft rock cavern,and that the optimum design method is worthy to be popularized.