Abstract: Ore drawing is the core work of Pillarless Sublevel caving,and the selection of the structural parameters in stope is an important work of ore drawing,it directly impacts on the mining efficiency and mining economic indicators(including recovery and dilution depleted).This paper firstly described the new understanding of the "high sublevel" and "large space" theory in practice,combined with specific studies in "high and different sublevel ore drawing" of Dahongshan-Iron MIining of Kungang,this paper carried out studies on optimization of ore drawing step with approach dimensions,optimization of approach spacing,respectively form laboratory similar simulation and software numerical simulation,got the answer that under the high and different sublevel ore drawing situation,reasonable ore drawing step indicator was 6.72～7.56m,reasonable approach spacing indicator was 25m,the optimization of the structural parameters of Pillarless Sublevel caving had a great significance to guide the work of ore drawing.