Abstract: The selective reduction of NO in an oxygen-rich environment with biomass-derived activated carbon supported potassium catalyst was investigated. The. results show that in comparison with coal (lignite) based activated carbon supported potassium catalyst, biomass (sawdust) based activated carbon supported potassium catalyst exhibits a high selectivity for the reduction of NO_x to N₂, keeping a high and stable activity with NO reduction of about 80% during 2 h-isothermal experiment as well as a relatively low activity with the oxygen-carbon reaction of 18%. XRD, BET, XPS and TPD results indicate that the excellent catalytic performance of the biomass-derived activated carbon supported potassium catalyst is associated with the highly dispersion of active potassium species, which might result from the high surface area and the large amount of surface oxygen groups. Furthermore, the selective emission of CO₂ with regard to CO is an additional benefit of using biomass-derived activated carbon as the support for NO reduction.