Abstract: Through field collecting coal samples in No.4 coal seam of Zhujiadian coal mine,the programmed temperature rising test and gas chromatograph are applied to study the production and change laws of CO,CO₂ and C₂H₄ gases during the coal oxidized spontaneous combustion process,and the curve rules of φ(C₂H₄)/φ(C₂H₆),φ(C₃H₈)/φ(C₂H₆) and other alkene/alkane ratio are analyzed.The test proves that spontaneous critical temperature of No.4 coal seam is 60~70 ℃,dry cracking critical temperature is 90~110 ℃.During the temperature programming process,the oxygen consumption rate and exothermicity of coal samples are rapidly increased after 90~110 ℃.CO,C₂H₄,C₃H₈ can be taked as coal spontaneous combustion index gas for No.4 coal seam,and φ(CH₄),φ(C₂H₄)/φ(C₃H₈),φ(C₂H₄)/φ(C₂H₆) can be taked as auxiliary indicators,which provides a theoretical support for fire prevention technology,fire monitoring and early warning of Zhujiadian coal mine.