This study was carried out to investigate the changes in the composition of essential oils for the improvement of air-curing process of burley tobacco leaves. From the essential oils isolated from the cured tobacco leaves by steam distillation method, 90 compounds including 15 acids and esters, 19 alcohols, 23 aldehydes and ketones, 19 hydrocarbons, and 14 miscellaneous compounds, could be identified by gas chromatography and gas chromatography-mass spectrometry. Among them, acids and esters were gradually decreased during the progress of curing after harvesting. A rapid increase in alcohol content was observed in the earlier stage of curing, but thereafter, decrease followed until the end of curing However, aldehyde and ketone groups were continuously increased during curing and were 3 times higher in quantity after curing than at the harvesting time. The concentration of hydrocarbons was increased in the earlier stage of curing, but gradually decreased from the middle stage. The miscellaneous compounds were continuously increased in content until the end stage of curing, with rapid increased in the earlier stage of curing.