Abstract: The thermal analysis was used to study the oxidation and thermal degradation reaction of coal with different oxidation degrees of coal. The results showed that in the air this reaction of coal could be divided into five stages, e.g. moisture content vaporizing, weighing by absorbing oxygen, thermal degradation by heating, firing, and firing last. The two stages of coal's oxidation, weighing by absorbing oxygen and degradation by heating, were studied. The oxidation reaction of weighing by absorbing oxygen is a first-order chemical reaction, and the thermal degradation reaction by heating is a 3/2-order chemical reaction. The average activation energy E and lnA at different stages of oxidation were calculated. The feature of oxidation process and the rule of E and lnA at different oxidation processes were analyzed. A reliability of calculated kinetic parameters of the oxidation reaction was checked by the drawing method.