Abstract: Ore drawing is the core work of the pillarless sublevel caving method，and the selection of the structural parameters in stope is an important work of ore drawing，which directly impacts on the mining efficiency and mining economic indicators (including recovery and dilution depleted).The main structural parameters of the stope are sublevel height，access space and caving step.According to the theory of ore drawing，different combinations of these three parameters will affect the final index.Large structural parameters combination of 20×20m was used in phaseⅠof Dahongshan iron mine，and sublevel height and access space were both 20m.phase II planned to adopt 30×20m structural parameters combination，that is，the sublevel height is raised to 30m，which belongs to high and variable sublevel ore drawing.In connection with the high and variable sublevel ore drawing in Phase II Project of Dahongshan Iron mine，similar materials in laboratory were used to produce ore drawing model and conduct low dilution ore drawing research，achieving the developmental morphology of drawn-out ore-body，optimal caving space and intersection hole under high and variable sublevel condition.The test results prove that the low dilution ore drawing significantly improved resource recovery，and effectively reduced ore loss and dilution.

Key words: High and variable sublevel, Low dilution ore drawing, Recovery, Dilution rate, Parameter optimization