A total of 559 flue-cured tobacco samples with 3 grades (B2F, C3F and X2F) were collected from the main tobacco-growing areas in Hunan Province, and their sulfur contents were determined to study the regional characteristics of the sulfur contents and their quantitative correlations with the evaluation indices of smoking quality. The results showed that the sulfur content in the flue-cured tobacco was 0.100%-2.106% , with a mean of 0.884%. The samples with sulfur content above 0.7% accounted for 71.56% of the total. The sulfur content decreased gradually from the high sulfur content area of Central Hunan to South Hunan and Northwest Hunan. With increasing sulfur content in tobacco leaf, the aroma quality, aftertaste, combustibility and ash color went to bad, offensive odor and irritation property increased, and aroma taste, eat-taste and total smoking quality score fell down. Under the influence of applying larger amount sulfate potassium and of sulfur-type acid precipitation, the sulfur content in tobacco leaf was somewhat higher in partial areas of Hunan Province, and gave negative impact on tobacco quality, being one of key factors limiting the improvement of tobacco quality and ought to be attached enough importance in tobacco production.