Abstract: In this paper, we analyzed the widely adopted leakage mechanism and their corresponding applications of loose circle around roadways and boreholes and the fractures produced by the driving of roadway and borehole. We proposed that the air in the roadway successively flows into the borehole through the loose circle around the roadway. It shows different air leakage process at different stages of borehole extraction. We also analyzed the applications of these air leakage mechanisms in the depth of borehole sealing; that are "two sealing and one grouting" pressurized borehole sealing method and second hole sealing method. Finally the key problems need to be solved for borehole sealing efficiently were pointed out.