Abstract: In order to determine the reasonable sealing depth of the drainage borehole in the coal seam along lane W33011 of Sihe Coal Mine and improve sealing quality, based on the mine geological conditions, FLAC^3D numerical simulation software is used to simulate the stress distribution and fracture development of coal body around the roadway after the roadway excavation, and YFZ3 hole sealing quality detector is used to detect the hole sealing quality and leakage position, and determine that the reasonable drilling depth in the test area is 14 m, which effectively improves the gas drainage effect.