Cyclic desulfurization-regeneration-denitrification of activated carbon (AC) has been widely used as a cost-effective integrated process for the simultaneous removal of SO2 and NOx. In this work, the influence of cyclic desulfurization and regeneration (C-S-R) on selective catalytic reduction (SCR) of NOx by NH3 was systematically investigated. The results indicated that the SCR activity of AC significantly improved after several desulfurization and regeneration cycles. Different characterization tests were carried out to reveal the internal correlations among the structures, acid/redox properties and SCR activities of the regenerated carbons. Results showed that the increased phenol, anhydride and ester groups were mainly responsible for the enhanced SCR activity, which not only promoted the oxidation of NO to NO2, but also increased the NH3 adsorption. Furthermore, in situ diffuse reflectance infrared transform spectroscopy (DRIFTS) results indicated that the SCR reaction over regenerated carbons mainly obeyed the Eley-Rideal mechanism and the Lewis acids induced by anhydride and ester groups played significant roles in SCR reaction. Hence, the promoting effect of C–S-R on denitrification strongly supports the sustainability of AC in reducing pollution emission and facilitates cleaner production.