FM/ACFN and Ce-doped CFM/ACFN low-temperature catalysts are prepared by an impregnation method that takes polyacrylonitrile-based activated carbon fiber modified with nitric acid as the carrier. The catalysts are characterized by X-ray diffraction, scanning electron microscopy, Fourier-transform infrared spectroscopy, and thermogravimetric analysis. The effects of temperature, oxygen, and sulfur dioxide on the adsorption and removal of NO by catalyst are studied by laboratory gas distribution. Results show that the addition of metal oxide can increase the ability of chemical adsorption of NO by ACFN by 2.5%, and the ability of catalytic reduction of NO can be increased by up to 14%. Under the condition of oxygen and ammonia as reducing agent at 250 degrees C, the ability of metal-oxide-loaded ACFN to catalyze the reduction of NO can reach up to 68%. The addition of Ce does not completely inhibit the decrease of the ability of the catalyst in treating NO under sulfur-containing conditions, but it can maintain the catalyst's reducing ability at a relatively stable level, and the presence of SO2 will reduce the redox capacity of ACFN itself.