Abstract: Contents of polyphenol (chlorogenic acid and rutin), lipid, starch and protein, and activities of relevant enzymes, including PPO, lipoxygenase, α-amylase, and proteinase, in redried lamina of flue-cured tobacco were examined during aging. Results showed that the contents of polyphenol, lipid, starch and protein decreased by 20.0%, 15.0%, 11.5% and 12.2%, respectively, during the aging of 18 months. After the aging of 18 months, no significant changes occurred in the contents of rutin, starch, protein, yet the lipid content changed significantly (P≤0.05), the content of total polyphenol and chlorogenic acid changed much significantly (P≤0.01). The activities of polyphenol oxidase, lipoxygenase, amylase and proteinase all decreased during the whole aging. After aging of 18 months, the activities of four enzymes had highly significant difference(P≤0.01) with those before aging.