Abstract: DTG-60H thermobalance was used to study combustion characteristics of samples from Yuanbaoshan and Datong with different average sizes.The heating rate was 30 ℃•min^-1,O₂ flow rate was 80 ml•min^-1.Particle sizes of pulverized coals were analyzed by Malvern MAM5004 Laser Mastersizer，made in the United Kingdom. In terms of experimental data, the combustion process was divided into two regions as the low temperature region and high temperature region, and the chemical kinetic parameters of each region were determined.The differences of combustion characteristics between micro-pulverized and common-pulverized coal were discussed.