Basic oxygen furnace steelmaking leads to the production of CO-rich off-gas. When CO and NO are combined in off-gas, selective catalytic reduction by CO (CO-SCR) effectively achieves the synergistic removal of both pollutants. In this paper, CuCeZrO, MnCeZrO, and FeCeZrO catalysts are prepared and evaluated for their CO-SCR activity, and the results show that the reaction system needs to be anaerobic; thus, the CO-SCR reaction can be dominant. The T values of CuCeZrO and FeCeZrO are 200 °C and 223 °C, respectively. The activities of these two catalysts are higher than that of MnCeZrO (T = 375 °C). Linear nitrate and bridged bidentate nitrate are the main intermediate species involved in NO conversion on the catalyst surface, and bidentate CO coordination is the main intermediate species involved in CO conversion on the catalyst surface. CuCeZrO has high lattice oxygen mobility and is more likely to react with NO and CO. In the presence of oxygen, most CO is oxidized by O, which increases continuously to 100%, 100%, and 98% for CuCeZrO, FeCeZrO, and MnCeZrO, respectively; additionally, CO is oxidized by O, and the CO-SCR reaction cannot be carried out.