After activation, GY-AFA and PS-AFA showed catalytic activity, and their NO removal efficiency increased from 10% and 9% to17% and 64%. This suggested that some groups on activated fly ashhave played a role in catalysis, and the content of this groups inPS-AFA was much higher than that in GY-AFA. According to theresults of FTIR, XPS, TG and Py-FTIR, silica sulfuric acid was considered as the active component of the catalytic reaction.