Abstract: Ce-Co-La-O composite oxide support was prepared by a modified coprecipitation method and the Cu-based catalyst (Cu/Ce-Co-La-O) was then obtained through incipient impregnation; the performance of the Cu/Ce-Co-La-O catalyst in the selective reduction of NO with propylene in excess oxygen was investigated and the relationship between the catalyst structure and performance was explored by means of surface area measurement, X-ray diffraction (XRD), temperature-programmed reduction (H₂-TPR), pyridine absorption infrared spectrum (Py-IR), thermal gravimetric analysis (TG) and scanning electron microscope (SEM). The results indicated that Co promoter can increase the amount of Brnsted acidic sites of the Cu-based catalyst and enhance its reducibility. La promoter can further increase the amount of Brnsted acidic sites and the catalyst thermal stability. Meanwhile, Ce-Co-La-O may form a sosoloid and have a synergistic effect on the catalytic performance of Cu/Ce-Co-La-O. Consequently, the Cu/Ce-Co-La-O catalyst exhibits excellent low-temperature activity and thermal stability in the selective reduction of NO; the conversion of NO reaches a maximum of 81.6% at 250 ℃ and is still 52.5% even at 600 ℃.