Abstract: In order to solve the problem that gas in the upper corner and return air tunnel is over limit,master gas effusing law of working face,the 33204 working face in Xuandong Second Coal Mine where use "U+L" ventilation was selected as the research object.Through the layout of measuring points in the working face,detection of air volume and gas concentration,the gas effusing law of 33204 working face along trend and the inclination of gas emission,as well as the gas emission coefficient of coal wall and goaf was concluded by data processing,numerical simulation analysis and regression processing.It provided the necessary theoretical basis and technical guidance for mine ventilation management,gas drainage design and gas control.