Abstract: In this study,three kinds of kinetic models were used to simulate the simultaneous desulfurization and denitrification process by biofilm-packing tower.The results indicated that the biochemical degradation reactions of SO2 and NOx in the biofilm were both the first-order reactions and fast-rate biochemical reactions.According to the Adsorption-Biofilm Theory and its kinetic model,the outlet mass concentration,biochemical removal and purification efficiency of NOx were simulated and compared.The results indicated that there were good relativities between the theoretical and experimental values by applying this theory and its kinetic model (the correlation coefficients were in the range of 0.70—0.99).By applying the Adsorption-Transmittance and Biodegradation Mechanism and its kinetic model,the outlet mass concentration,biochemical removal and purification efficiency of NOx were simulated and compared.The results indicated that there were good relativities between theoretical and experimental values of the NOx mass concentration in outlet and biochemical removal by applying this theory and its kinetic model.The correlation coefficients of them were 0.99 and 0.89,but the relativity of purification efficiency between the theoretical and experimental values was not high (the correlation coefficient was only 0.55).