In the gas extraction of high gas and low permeability coal seam, there are some problems like small effective extraction range, low extraction efficiency and long extraction period. It is proposed to use CO2 phase change fracturing enhanced extraction technology to improve the pumping. The process characteristics of CO2 phase change fracturing technology was introduced, the principle of CO2 phase change fracturing enhanced extrction technology was analyzed, and the gas extraction effect before and after cracking by field test method was studied. The research showed that the CO2 phase change fracturing technology can significantly improve the permeability of the coal seam,with a good effect of increasing the permeability and extrction. After the CO2 phase change fracturing in the heading face, the average gas extraction volume fraction before cracking increased by 1.71 times. The average gas extraction pure quantity increased by 1.96 times, and the sampling time was greatly shortened. During the excavation, the gas volume fraction of the return airflow was basically maintained below 0.6%,with remarkable gas control effect.