The copyrolysis and cocombustion behaviors of Pingshuo coal and the biomasses (sawdust and rice straw) have been investigated using a thermogravimetric analyzer. The experimental results indicate that there exist synergetic effects between the biomasses and Pingshuo coal during their coconversion process. The initial temperature of volatile emission from Pingshuo coal and the temperature corresponding to the maximum conversion rate during the copyrolysis change with the biomass mixture ratio. Moreover, it can be deduced from the comparison between the experimental and the calculated DTG curves that the copyrolysis process is not the sum of Pingshuo coal and the biomass conversion. During their cocombustion process, the larger the mixture ratio of the biomass is, the lower the ignition temperature and the burnout temperature are, and the larger the combustion characteristic index is. In addition, the maximum combustion rate and the combustion performance are the best when the mixture ratio of the biomass is 70 wt % in the research. Moreover, the activation energy and the frequency factor of the copyrolysis and the cocombustion were calculated by the Coats-Redfern method and the first-order reaction model. The results show that the activation energy and the frequency factor change with the mixture ratio of the biomass, and the regularity was consistent with the above-mentioned conclusions. Therefore, it can be deduced that the addition of the biomass can facilitate the pyrolysis and the combustion of Pingshuo coal, and improve the utilization field of Pingshuo coal.