Abstract: The selective catalytic reduction (SCR) of NOx using MnOx and CeO2 supported on viscosebased active carbon fibers (ACF) at 120℃～270℃ relatively lower than the temperature when using V2O5/TiO2anatase catalyst was studied. As a result, CeO2/ACF shows a better catalysis than MNOx/ACF, which is not affected by the reaction temperature. NO conversion of 85% is reached with the 10%CeO2/ACF catalyst at the whole temperature window. Furthermore, a series of MnOxCeO2/ACF composite catalysts were studied. The results show that the loading method of catalyst affects its activity.