Abstract: Characteristic parameters of low temperature oxidation of five kinds of mixed coal samples made of different sizes are studied through programming temperature test. Based on the analysis of carbon dioxide concentration, carbon monoxide concentration and the critical temperature under the condition of different coal temperature and air supply amout, we obtain influence laws of air supply amount on coal low temperature oxidation properties in the process of spontaneous combustion, and determine the quantitative relation of carbon monoxide concentration and coal temperature, air supply volume, reveal that the curve relation of carbon monoxide concentration, coal temperature and air supply volume conforms to the trend of exponential growth.