Two types of manganese ore were tested as simultaneous SOx and NOx removal agents in dry condition. It was found that manganese oxide has the dual function of De-SOx and De-NOx and that the SOx removal efficiency of simultaneous De-SOx and De-NOx operation is almost the same as that of individual De-SOx operation. In addition, a higher NOx removal efficiency was obtained at high temperatures compared with individual De-NOx operation. We found that there was a large difference in removal efficiency between the two manganese ores, which can be attributed of the manganese ore's surface areas. The influence Of O-2 concentration of tested range on De-SOx efficiency in simultaneous De-SOx/De-NOx operation was not observed. Over 90% of NOx removal were achieved at about 10% O-2 concentration for simultaneous DeSO(x)/De-NOx experiment, which was higher than individual De-NOx experiment.