A tubular reactor with a sequence heating device is used to discuss the effects of operational parameters for the reaction between nitric oxide and ammonia. Experimental results showed that denitration efficiencies had been developed to become a parabola with the change of reaction time under a certain NH3/NO mole ratio and under a certain temperature and that denitration efficiencies also had changed to become a parabola with the increase of the reaction temperature when a NH3/NO mole ratio was identified. Denitration efficiencies of 91.6 percent could be reached when the optimal NH3/NO mole ratio, optimal reaction temperature, and reaction time respectively were 1.2, 320 ℃ and 14min in this work.