Abstract: The sealing quality of gas extraction boreholes can directly affect the extraction efficiency. In order to effectively guarantee the sealing quality of gas extraction boreholes, the possible air leakage crack and its controllability after the sealing of gas extraction borehole are qualitatively analyzed, and the difficulty of forming the air leakage path is compared accordingly. The results show that there may be six types of cracks inside and outside the gas extraction boreholes after sealing, including loose circle cracks in the surrounding rock of the roadway, cracks around the support device, primary cracks inside the coal seam, cracks around the borehole, cracks in the sealing material, and cracks in the extraction pipe; correspondingly, there are seven kinds of leakage paths that may be generated by gas extraction boreholes, among which the most likely leakage path is air inside the roadway to loose circle cracks in the surrounding rock of the roadway to cracks around the borehole to extraction boreholes to extraction pipes. Based on this, combined with the shortcomings of the existing gas extraction borehole sealing device and the actual conditions of its field application, starting from the principle of cutting off the connection between the air leakage nodes, eliminating the air leakage nodes and blocking the air leakage path, a new type of drilling hole sealing device that can be recycled and re-sealed for many times is proposed.