Abstract: In order to reveal the mechanism of TSNAs formation in stored burley tobacco leaves and screen the substances which inhibit TSNAs formation, an experiment was designed to investigate the effects of oxidant and antioxidant treatments on TSNAs formation in burley tobacco leaves stored at high temperature. Ozone was used as an oxidant, vitamin C(VC), vitamin E(VE) and caffeic acid as antioxidants. The results showed that ozone treatment promoted the formation of TSNAs in burley tobacco leaves significantly, and the promoting effect significantly enhanced with the duration of ozone treatment. The total content of TSNAs in burley tobacco treated with ozone for 12 hours every day was 7.83 times that in leaves without ozone treatment. The difference of total TSNAs content reached extremely significant level between the treatments. Among the selected antioxidants, VC solution presented the most significant inhibitory effect on TSNAs formation.