Abstract: The statistical analysis of pressure relief gas extraction data is carried out for 12 working faces with different air distribution and different operation states of mine main fans in three mines of Yangmei Group in recent years. The pressure relief gas extraction rate at mining face is inversely proportional to the air distribution. When the gas extraction system capacity is determined, increasing air distribution volume of working face can reduce the gas extraction rate; increasing wind-exhaust gas quantity can even increase gas concentration at upper corner, return-air current and gas drainage roadway, which deviates the expected goals. Pressure relief gas in goaf continously moves to return-air side of "O" ring channel at the top of caving zone under the function of buoyancy and wind flow field, and forms the best region of pressure relief gas extraction.Strengthening the gas extraction is the key to guarantee safe and efficient production.