WO3-CeO2-TiO2 catalysts for NO (nitrogen monoxide) reduction by ammonia were prepared by a sol-gel method. The catalysts were characterized by BET, XRD, Raman, NH3/NO adsorption and H2-TPR to investigate the relationships among the catalyst composition, structure, redox property, acidity and deNOx activity. WO3-CeO2-TiO2 catalysts show a high activity in a broad temperature range of 200-480 ℃. The low-temperature activity of catalysts is sensitive to the catalyst composition especially under low-O2-content atmospheres. It may be related to the synergistic effect between CeOx and WOx in the catalysts. On one hand, the interaction between ceria and tungsten oxide promotes the activation of gaseous oxygen to compensate the lattice oxygen consumed in NH 3-SCR (selective catalytic reduction) reaction at low temperatures. Meanwhile, the Brnsted acid sites mainly arise from tungsten oxides, Lewis acid sites mainly arise from ceria. Both of the Brnsted and Lewis acid sites facilitate the adsorption of NH3 on catalysts and improve the stability of the adsorbed ammonia species, which are beneficial to the NH3-SCR reaction. WO3-CeO2-TiO2 catalysts for NO (nitrogen monoxide) reduction by ammonia were prepared by a sol-gel method. The catalysts were characterized by BET, XRD, Raman, NH3 / NO adsorption and H2-TPR to investigate the relationships among the catalyst WO3-CeO2-TiO2 catalysts show a high activity in a broad temperature range of 200-480 ° C. The low-temperature activity of catalysts is sensitive to the catalyst composition especially under low- On one hand, the interaction between ceria and tungsten oxide promotes the activation of gaseous oxygen to compensate the lattice oxygen consumed in NH 3-SCR ( Both of the Brønsted acid sites mainly arise from tungsten oxides, Lewis acid sites mainly arise from ceria. Both of the Brnsted and Lewis acid sites facilitate t he adsorption of NH3 on catalysts and improve the stability of the adsorbed ammonia species, which are beneficial to the NH3-SCR reaction.