Abstract: The hydrogeological conditions in mining area with complex geology are more complicated, and the pores and cracks in rock seam are more developed. If sealing technology is not reasonable, the result of measured gas pressure in coal seam would not accurately reflect actual situation of gas in coal seam. For the problem, four groups of pressure measuring points with twelve pressure measuring boreholes are arranged in 5 and 6-1 coal seams of Hongyu Coal Mine of Guizhou Jiuyi Coal Mining Co., Ltd. for gas pressure measuring test, and boreholes in each group are sealed by use of three kinds of normal hole-sealing technologies including grouting hole-sealing, short capsule plus grouting hole-sealing and long capsule pressure mucus hole-sealing separately. Application effects of the three hole-sealing technologies are analyzed according to test results, and adaptation conditions are obtained as following: the grouting hole-sealing technology is applicable for deeper rock hole with finer and harder rock, the short capsule plus grouting hole-sealing technology is applicable for downward borehole with larger inclination angle, and the long capsule pressure mucus hole-sealing technology is applicable for borehole in roof and floor with broken rock or possible aquifer in coal seam.