Abstract: In order to optimize the division boundary optimization of inclined coal seam in open-pit mine under the erosion condition of burnt rock,the characteristics of burnt rock occurrence and the randomness of coal and rock occurrence in Xinjiang coalfield were analyzed.Taking Heishan Open-Pit Coal Mine of Shenhua Xinjiang Energy Co.,Ltd.as the background,by constructing the simulated mining boundary,the variation rule of boundary stripping ratio and average stripping ratio with the expansion of the partition boundary was revealed,and the principles and applicable conditions for the division boundary of the burnt rock erosion in open-pit mines were determined.The SMCAD software were used to construct the 3D simulation boundary of the Heishan Open-Pit Coal Mine.The method of verifying the three-dimensional state by the block inverse method was established by establishing the block model of coal and rock layered attributes.This research results have been applied in the mining practice of the Heishan Open-Pit Coal Mine.The research results show that the economic reasonable stripping ratioof Heishan Open-Pit Coal Mine is 8.06 m3/t,which meets n0 (boundary stripping ratio )is 4.4 m3/t≤nj(economic reasonable stripping ratio).That is,there is a reasonable state determined based on the principle that the "state stripping ratio is less than or equal to the economically reasonable stripping ratio"; The block amountreverse test was used to obtain the block stripping ratio and the block size outward expansion level stripping ratio,which realizes the rationality of the reverse tests design realm from the 3D perspective,with the block amount reverse tests to determine division boundary ratio width=71,height=16,dpi=110 m3/t≤nj,and the reasonable boundary and maximize the economic benefit of the open pit mine under the condition of burnt rock erosion.