Based on bad gas permeability, high gas bearing capacity and soft structure in No.3 coal seam of Xingjing Mine, water layer drilling hydraulic fracturing pressure relief technology was put forward and its principles were analyzed. Meanwhile, fracturing technology, technical parameters and facility were selected and designed, which had better gas drainage effect through field test and got index parameter of hydraulic fracturing. All of these provided guidance for highly promotion of hydraulic fracturing pressure relief technology in low permeability and high gas outburst seam of Xingjing Mine and even in Yangquan mining area.