Lower segment of 27131 mining working face of Yanmazhuang Mine with top seam mining, the initial gas content of coal seam is 16.45 m3/t, far more than outburst critical value 8 m3/t, with coal and gas outburst threat, bringing danger to working face recovery mining. In order to eradicate the outburst danger, a series of safe technology was adopted to improve the judge of gas drainage effect and ensure the safe recovery mining.