Controlling SO2emissions in an unpulverized-coal-fired Rijke-type pulsating combustor is performed by burning with the limestone or dolomite additive. A series of parametric study are conducted to better understand the performance and mechanisms of the SO2capturing process in the pulsating combustor. Results show that the SO2reduction efficiency is dependent on the mass ratio of additive to the sulfur in fuel, but independent on the type of calcium carbonate additives. Particle size of additives has significant effect on SO2reduction efficiency particularly in small size subrange. The SO2capturing process is proved to be diffusion-controlling in the present pulsating combustor. It is found that the presence of CO in the combustor suppresses the SO2reduction capability.