Abstract: With the background of loose and low permeability coal seam gas control project in Sijiazhuang Coal Mine, COMSOL software is used to simulate the stress and permeability evolution of coal surrounding the boreholes and characteristics of gas flow. On this basis, considering the mutual interference among boreholes into account, the gas extraction scheme was designed and field practice was carried out. The results show that, after using the hydraulic flushing technology, the footage of boreholes decreases by 45.9 %, while the gas concentration increases by 3 times and the gas extraction increases by 1.9 times, the effect of gas drainage has been greatly improved.