Abstract: Based on field experiments, the influence of the application of sodium selenite in selenium-deficient soils on selenium content, quality of flue-cured tobacco and the safety of cigarette were analyzed, and the suitable application amount was determined. The results indicated that:(1)The selenium contents of flue-cured tobacco showed a parabolic trend with the increase of the application amount of sodium selenite, with the highest selenium content observed when the application amount was 13.50 kg/ha.(2)When the application amount of sodium selenite in soils ranged from 6.75 to 11.25 kg/ha, the contents of chemical components in tobacco leaves were suitable, the chemical component usability and the smoking quality of tobacco were better.(3)Acute toxicity, mutagenic ability and the ability of inducing oxygen free radicals of selenium-rich cigarettes were lower than that of selenium-deficient cigarettes. By comprehensively analyzing, the suitable application amount of sodium selenite in tobacco-planting soils was determined as 6.75-11.25 kg/ha.