Abstract: In recent years, the non-pillar sublevel caving method has been applied in underground iron mines widely, and the size parameters of the stope are increasing.In order to comply with the law of ore-drawing and improve the economic index of mining, the optimization of the blast rings space is especially important.In this paper, combined with the production practice of the non-pillar sublevel caving method used in Meishan iron mine, the PFC3D software was used to establish the ore-drawing model, and the corresponding FISH program was compiled to control the flow of the ore particles.The preliminary design of the six sets of blast rings space was simulated, and the optimum blast rings space was 2.2 m under the condition of 18 m×20 m stope size parameters.It has been verified by on-site industrial tests that the recovery rate and depletion rate of the optimum blast rings space are significantly improved.