Abstract:Industrial experiment has approven that hydraulic cutting measures can ensure the safety of heading in coal seam,rapidly eliminate the risk of coal and gas outburst after cutting,improve the speed of heading in the district in which coal and gas outburst possibly happen.the parameters relating to hydraulic cutting,such as high pressure water jet,ground stress,gas internal force etc.,are analyzed,and the mechanism of preventing coal and gas outburst by hydraulic cutting is studied.