Abstract: In order to master the fire-extinguishing efficiency of different concentrations of CO₂ on the oxidized coal re-combustion, a self-developed coal spontaneous oxidation program temperature increasing experimental device was adopted to study the inhibitory effect of CO₂ on coal oxidation and heating process, and the samples of Pingdingshan No.8 Coal Mine were fed with CO₂ concentrations of 10 %, 20 %, 30 % and 40 % respectively.The oxygen consumption rate, the production rate of CO and the change law of apparent activation energy of coal were measured, and the result shows that different volume fractions of CO₂ have inhibitory effects on the heating process of coal oxidation.The results show that different volume fractions of CO₂ have an inhibitory effect compared with the oxidation under pure air conditions.At the same time, the larger the volume fraction of CO₂ introduced, the lower the oxygen consumption and CO generation rate both the primary and secondary coal oxidation process, while the higher the apparent activation energy.That is to say, the larger the volume of CO₂, the better the inhibition efficiency of the re-combustion process of oxidized coal.