Optimizing the boundary roof pillar in the transition from open-pit mining to underground mining is an important subject; this task including many decision variables and appraise indexes

so the methods given before can’t get the good result. This paper combining the genetic and 3D numerical simulation

the evolution numerical simulation method to globally optimize the boundary roof pillar is researched. The optimizing indexes and processes are given; the method has been used to optimize the boundary roof pillar in the transition from open-pit mining to underground mining of Daxingshan Iron Ore. And it is shown that the method is feasible. The scheme resulted by the method can guide the mining design for Daxingshan Iron Ore.