Abstract: The gas storage space in overlying strata of stope is the key to optimizing the layout parameters of gas extraction borehole and preventing abnormal gas emission. In this study, by combining numerical simulation and field test, the fracture distribution and gas storage space change law of the stope before and after grouting under different grouting pressure at 22301 overlying grouting in sepa-rated-bed face in Tunlan Mine were analyzed. The results show that when the grouting pressure increases, the fracture zone height decreases gradually, but the fracture compaction effect weakens gradually. Meanwhile, the height and width of the fissure zone in space decrease, and the range of mining-induced fissure ring gradually shrinks. In the horizontal direction, the compaction degree and range in the middle of the goaf are increasing, and the range of the relief zone and free space is gradually shrinking. Under the condition of overburden-separation grouting, the effect of gas extraction in high-level borehole can be effectively improved by appropriately increasing the angle of the borehole and reducing the construction height. The research results of this study can provide reference for the optimal layout of gas extraction borehole on the overburden-separation grouting working face.