Abstract. Ozone oxidation denitration process has become the most closely watched sintering flue gas denitration technology currently. In order to investigate the influence of different operating conditions on NO oxidation in practical engineering application of this technology, an ozone oxidation system was built, and sintering flue gas was extracted from the pipeline between the induced draft fan and the desulfurization tower. The influence of flue gas flow and inlet NO concentration on NO oxidation was investigated by orthogonal experiments. The results indicated that NO oxidation efficiency increased with the O3 yield of ozone generator and O3 dosage under any flue gas conditions. Under the same inlet NO concentration, NO oxidation efficiency decreased with the increase of flue gas flow. Under the same flue gas flow and O3 dosage, with the increase of inlet NO concentration, the O3 utilization rate increased while the average oxidation energy consumption of each NO molecule decreased, which was beneficial to promote the NO oxidation efficiency. In practical engineering application, the setting of O3 dosage should take into account both engineering design indicators and economy. Ozone oxidation denitration process could achieve NO oxidation efficiency higher than 90% through reasonable design, indicating a good industrial application prospect in the treatment of sintering flue gas.