Abstract: Aiming at the problems of stress concentration and significant ground pressure caused by the deterioration of the mining conditions of the second step pillar after the ore body is mined by the sublev⁃ el open stoping with subsequent filling mining method in an iron mine，this study carried out the optimal selection of the second step pillar mining scheme. Firstly，combined with the site engineering conditions and resource recovery requirements，three feasible mining schemes of sublevel open stoping with subse⁃ quent filling method，layered filling method and shallow hole shrinkage with subsequent filling method are proposed，and the technical and economic indexes of each scheme are determined. Then，the fuzzy com⁃ prehensive evaluation method is used to carry out the scheme optimization. Combined with the analytic hier⁃ archy process and Delphi expert scoring method，the weight distribution of each evaluation index is deter⁃ mined. The linear function method and binary comparison sorting method are used to calculate the fuzzy membership degree of quantitative and qualitative indexes respectively，and the membership degree matrix is constructed and the weighted average method is used to complete the comprehensive evaluation. The re⁃ sults show that the fuzzy comprehensive evaluation results of sublevel open stoping subsequent filling meth⁃ od，layered filling method and shallow hole shrinkage subsequent filling method are 0.487 6，0.452 5 and 0.419 3 respectively，and the evaluation value of sublevel open stoping subsequent filling method is the highest. The field application shows that this scheme can make full use of the original mining preparation project during the room mining，so that the integrity of the exposed filling body is good without collapse， and has good technical and economic indicators and safety. It provides a scientific and reliable decision�making basis for pillar mining under complex conditions，and has good engineering application value.

Key words: second step pillar, sublevel open stoping with subsequent filling, optimal selection of mining Method, fuzzy comprehensive evaluation method