Abstract: Changes in chemical components of flue-cured tobacco during fermentation and aging were studied.The results showed that the reducing sugar, total nitrogen, nicotine, protein, amino acids, total lipid and caroteinoid content decreased during fermentation and aging.But their content in aged leaves were much lower than that in fermented leaves.On the contrary, the total acids, total volatile acids, volatile carbonyl compounds, glucosides of flavor compounds increased during fermentation and aging.But their content in aged leaves were much higher than that in fermented leaves.