Abstract: As a completely new device for coal seam permeability improvement, carbondioxide blasting device can produce huge pressure due to instantly vaporized of liquid carbon dioxide on coal, which generates new cracks and extend the interal carcks and provides more flowing channels for gas.The research proved that permeability coefficient of coal seam improved 27.05 times, gas emission of borehole 6.73 times, quantity of gas drainage 4.66 times and the radius of gas drainage in borehole 11.25 times by carbon dioxide blasting device. Coal seam permeability improvement and yield-increasing effect of coal bed gas is ideal.