There are many ways to increase the combustion rate of pulverized coal. In this paper, it is improve pulverized coal combustion rate by the method of microwave modification. In order to study the mechanism of modification on pulverized coal, microstructure and chemical compositions of pulverized coal before and after modification were studied. The results show that the microwave modification only changes the nature of PC itself without change component in the lower microwave power condition. And with the modified time extension, the pore number of PC surface gradually increases and the specific surface area enlarges. The highest combustion rate of modified-coal is 85.4%, and it is increase 11.1% than the raw coal in the experiment condition.