Abstract: The extraction of overburden unloading gas by high level boreholes is an important technical tool for roof gas management in high gas mines. In order to further improve the effect of high level borehole gas extraction, physical similarity simulation was applied to analyze the morphological distribution characteristics of roof mining fissures. The formation and evolution rules of macroscopic gas flow channels in the mining area were studied and applied to Fluent simulation software to analyze the influence of high level drilling on the gas extraction effect in the mining area under different vertical and horizontal extraction distances, and then the optimized technical parameters for high level drilling is proposed. The results show that the height of the fracture zone of the test working face is 68 m and the height of the caving zone is 10.5 m. High level drilling in the horizontal gas flow channel and vertical gas transition flow channel will improve the extraction efficiency of the gas in the mining area. Combined with the numerical simulation study, the best extraction position of the test working face was 23 m vertically and 25 m horizontally from the coal seam. Taking into account the changing geological conditions of the working face and the construction of the borehole, two extraction boreholes with a spacing of 10 m were set in the same vertical layer, and the best extraction position was between the two boreholes. The gas extraction effect on site was good, ensuring the safe recovery of the working face.