Abstract: A series of RuO₂-Fe₂O₃ catalysts varied in RuO₂ loading were prepared by sol-gel method and used for selective catalytic oxidation of ammonia to nitrogen. The results indicated that all the RuO₂-Fe₂O₃ catalysts showed an excellent low-temperature catalytic activity and the RuO₂ loading played a key role in catalytic activity of ammonia oxidation. Moreover, the characterizations of BET, XRD, H₂-TPR and DRIFTS were employed to investigate the relation between the physicochemical property of catalysts and catalytic activity. The research results elucidated that the introduction of RuO₂ increased the surface area. The synergistic effect between RuO₂ and Fe₂O₃ enhanced the redox property and the catalytic activity of ammonia oxidation. Meanwhile, the RuO₂ loading gave the significant effect on surface acidity of catalysts. Lewis acid sites were predominant on the catalyst surface.