Abstract: To make full use of discarded lower leaves of flue-cured tobacco, the effects of temperature-programmed drying, low-temperature (40 ℃) drying, and air drying on the contents (mass fractions) of major aroma and active components were investigated by analysis of variance, principal component analysis and cluster analysis. The results showed that: 1) Drying methods significantly (P < 0.05) influenced the contents of major volatile aroma components and other substances such as malic acid, higher fatty acids, chlorogenic acid and rutin in tobacco leaves, while their effects on the contents of oxalic acid, citric acid, nicotine, solanesol and crude protein were not significant. 2) The contents of major chemical components and the comprehensive evaluation scores of the first principal component between the unsuitable tobacco leaves dried by the temperature-programmed drying and low-temperature drying did not reach a significant level. The contents of volatile aroma components, non-volatile organic acids, crude protein, nicotine, solanesol, and polyphenols in tobacco leaves dried by the two methods were 2 208-2 401 μg/g, 16.22%-17.87%, 12.22%-12.87%, 1.02%-1.08%, 0.52%, and 1.66%-1.74%, respectively. The contents of major volatile aroma components, malic acid, higher fatty acids, chlorogenic acid and rutin, and the comprehensive evaluation scores of the first principal component of air-dried tobacco leaves were significantly lower than those dried by the above two drying methods. 3) The scores of the first three principal components of tobacco leaves dried by the different drying methods were basically consistent with the results of systematic clustering: the distance between temperature-programmed drying and low-temperature drying was close, and air-dried tobacco leaves were clustered in its own category. 4) When unsuitable tobacco leaves were used for the extraction of nicotine, solanesol and crude protein, the air drying method was more suitable, while the temperature-programmed and low-temperature drying methods should be used for the extraction of polyphenols or aroma components.