Abstract: With the increase of mining deepness, the phenomena of methane concentration exceeding limits is often happen in the 2781 coal mining face, to find out the methane outflow law and ensure the safe work, the methane outflow of the coal mining face is mensurated and the methane source is analyzed in this paper. Based on the regression analysis, the methane outflow laws of coal wall and fallen-coal in coal mining face are obtained, and the methane concentration distributing law is gotten. Which are the techno-elements of adopting the aimed preventive measures.