Abstract: The open stope mining method was adopted in the first section of No.2 mining area in an Iron Mine.The untreated goaf has reached 400,000 m3 and the ore quantity of remained pillar is nearly more than 26 million tons after years of exploitation.In order to fully recover the mineral resources，the mine is planning to recover the pillars.As the untreated mined-out area is large and the remained pillar is the key support for maintaining the stability of mined-out area，the recovery or destroy of part of pillars may induce a certain scale of ground pressure activities which will threaten normal safe production of mine.So before the pillar stoping，the research on security of pillar mining area can guide the implementation of the pillar stoping，and ensure the pillar mining in safety.Combining with the actual situation in an iron mine and based on the theory of stress increment，the combination of engineering geological investigation，laboratory test with numerical simulation is adopted to research the pillar′s security about the first section in No.2 mining area and to determine the safety factor of each pillar.The research results showed that the pillars in the first section of No.2 mining area is in safety，and parts of pillars can be recovered.

Key words: Stress increment theory, Numerical simulation, Pillar recovery secutity