The active carbon fiber (ACF) loaded different contents of La2O3 catalysts were prepared, and their catalytic activities and durability for the purification of NO were investigated, and for comparison, those of ACF and HNO3/ACF for the title reaction were also investigated. The orthogonal experiment results showed that the best volume fraction of oxygen in the mixed gas was 5%, and the best air speed of mixed gas was 5000 m3 (m3 x h)(-1). The catalytic experiment results showed that the activity of HNO3/ACF was better than that of ACF when the temperature was below 414.08 degrees C, but the activity durability of HNO3/ACF was inferior than that of ACF. The activity and the activity durability of ACF could be markedly increased when it was loaded La2O3 catalyst, the activity center of the catalyst was La2O3, and the La2O3 catalyst best load amount was 20%, the activity of 20% La2O3/ACF would above 95% when the temperature was higher than 350 degrees C, and its activity durability was about 8 h, which was superior than most of the catalysts that had been reported. The results of FT-IR and TG experiments also showed that the NO purification principle of ACF and HNO3/ACF was different from that of La2O3/ACF, when NO was purified by La2O3/ACF, the competition reactions took place between CO and NO.