The behaviors of coal pyrolysis under microwave are not only affected by the microwave generator but also by the properties of the raw coal itself. In this article, two high volatile sub-bituminous coals, Yima coal and Indonesia coal, were pyrolyzed under microwave with a frequency of 2,450 GHz. The effect of coal sample characteristics, such as grain size, moisture content, and mineral matter, on the behaviors of coal microwave pyrolysis were studied in detail. The results show that these coal characteristics considerably affect the temperature rising and product composition.