The activity of slaked lime for the simultaneous absorption of SOx and NOx from flue gases of coal combustion has been studied using a fixed bed reactor at 90 degreesC. The slaked lime samples were prepared by swelling the natural lime using water vapor. It was found that NO and SO2 enhanced the adsorption of each other. The results of IR showed that SO2 was absorbed as SO42- salt by Ca(OH)(2) in the presence of NO; however, it was mainly absorbed as SO32- salt in the absence of NO. It is interesting that NO could not be absorbed by the slaked lime without SO2 at the low temperature, while it was converted to NO3- salts with the presence of SO2. This implied that some species formed from SO2 played a role as catalysts for the adsorption of NO by the slaked lime, which indicated a possible way to remove SOx and NOx simultaneously from the flue gases of coal combustion.