Abstract: The control of heavy metal arsenic pollution in middle-low-temperature flue gas of coal-fired power plants is facing severe challenges. Seven adsorbents including pure Fe₂O₃, pure CeO₂, pure La₂O₂CO₃, FeCeO, FeLaO, CeLaO and FeCeLaO are prepared by co-precipitation method. The samples are characterized by XRD, BET, H₂-TPR, Raman and SEM-EDS techniques. The results suggest that the synergistic effect of Fe, Ce, and La is conducive to the formation of more low-temperature active sites and oxygen vacancy defects. The oxidation and enhanced adsorption characteristics of the adsorbents on As₂O₃(g) in flue gas at different temperatures are investigated. The results show that both Fe₂O₃ and La₂O₂CO₃ are effective active components for As₂O₃ adsorption, and CeO₂ is a good structural assistant. The composite adsorbents FeLaO, CeLaO and FeCeLaO all exhibit excellent oxidation/adsorption activity at 200~400℃, and can oxidize As(III) to As(V) by 100% even at low temperature of 200℃. Among them, FeCeLaO has the strongest adsorption activity, and the total adsorbed arsenic reaches 583.7μg/g, which is 1.8 times that of pure Fe₂O₃. This is due to the synergistic effect of Fe, Ce and La, leading to stronger oxidation activity and adsorption capacity of the composite oxide at middle-low- temperatures.