Abstract: Taking 18# ore-body of steep narrow vein in Jinchanggouliang gold mine as the basis，it is measured that the single drain port face-end ore-drawing bodies are cut by hanging-foot side wall and end wall under incline side wall condition by physical simulation experiment.The drawn ore-body is irregular in sharp and inclines forwards to the end wall and the hanging wall.The funnel that is formed by ore-rock contact surface shows as a 1/4 standard funnel of a whole besides little cutting by the footwall.Waste rock in bulk flow process mixes along the hanging wall and end wall，and ore loss at footwall are huge.To improve the flow properties of bulk and reduce the loss and dilution of ore，the optimal layout of ore drawing route is designed，that is，it should be arranged along the footwall vein and try to approach the drawing equipment to the footwall.Based on the flow law of bulk discovered，the bulk flowing may be divided into three zones of free fall zone，transition zone，and tilted side wall control zone in the height direction.Following the principle of the segment height being controlled within the transition zone，and considering the capacity of drilling equipment，the actual corresponding optimal segmentation height should be determined to be 12m and 14m.Finally，numerical simulation method was applied to optimize and obtain minimum safe distance of haulage drifts at 6m.The study provides technical support for efficient and safe mining of similar steep narrow veins.

Key words: Steep narrow veins, Pillarless sublevel caving, Optimization of structural parameters, Flowing law of bulk, Numerical simulation