Abstract: Based on four seam coal samples from Pingshuo Mining Area as the study objects, the programmed temperature rising test was applied to the key study on the variation laws of the CO, C2H4 and H2 gases during the coal oxidized spontaneous combustion process.Meanwhile, a comparison analysis was conducted on the variation laws of the gases from different seams in a same mine and the gases from the same seam of different mines. The test results showed that the critical temperat ure of CO produced from Pingshuo coal was 60~70 °C, the temperature of C2H4 appeared was about 120 °C and the critical temperature of H2 occurred was 90 °C.The H2 production quantity would be increased firstly with the coal temperature increased and then would be reduced in a variation tendency. The index gas to check the coa 1 spontaneous combustion in Pingshuo Mining Area would be CO and C2H4 mainly and H2 secondary.