Abstract: Aim at the condition of mining over collapse borderline in Meishan Iron Mine, and base on the natural equilibrious arch theory with computer simulation technology, this article study on preferences of sublevel open-stope succeed by fill and bottom structure of stope disposition, as well as the technics characteristic of this mining method, analyzed wall rock stress and displacement variation rule and plastic zone distribution, educed the roof terrane tensile stress is the key factor of effect stope stability.Then, use the index of maximum tensile stress of roof terrane bear ability to scale the stope stability, and optimized the stope structure parameters by orthogonal test.At the last, this study gained the parameters of 14m room stope width, 10m pillar stope width and 8m roof thickness can satisfy the mining over collapse borderline in Meishan Iron Mine.

Key words: Natural equilibrious arch theory, Displacement variation rule, Plasticzone, Roof terrane tensile stress, Orthogonal test