Abstract: Based on the fuzzy matter-element theory，a reasonable evaluation index of rock stability is chosen，and the fuzzy matter-element model of rock stability is finally built through the calculation of membership. In order to avoid the subjectivity of weight determination，the sum normalization method is adopted to determine the comprehensive weight of evaluation index，and then according to the calculating result of membership and the principle of maximum correlation degree，the multi-index comprehensive evaluation of stability grades for underground surrounding rock of Chambishi Copper Mine is realized. The results show that it is effective and feasible to evaluate the rock stability with fuzzy matter-element theory，and what's more，it offers a new thought to do this. Fuzzy matter-element|Stope stability|Membership|Evaluation index|Correlation Based on the fuzzy matter-element theory，a reasonable evaluation index of rock stability is chosen，and the fuzzy matter-element model of rock stability is finally built through the calculation of membership. In order to avoid the subjectivity of weight determination，the sum normalization method is adopted to determine the comprehensive weight of evaluation index，and then according to the calculating result of membership and the principle of maximum correlation degree，the multi-index comprehensive evaluation of stability grades for underground surrounding rock of Chambishi Copper Mine is realized. The results show that it is effective and feasible to evaluate the rock stability with fuzzy matter-element theory，and what's more，it offers a new thought to do this.

Key words: Fuzzy matter-element, Stope stability, Membership, Evaluation index, Correlation