Abstract: The acidic, neutral and basic aroma components in upper, middle and lower leaves of flue-cured tobacco before and after dry ice expansion were extracted with simultaneous distillation and extraction (SDE), and then analyzed by GC/MS with internal standards. Sixteen basic components, such as pyrazine, thiazole, pyrrole, and etc., seventeen netrual components, furaldehyde, linalool, β-ionone, and etc., and fifteen acids, propionic acid, 2-methyl valeric acid, benzoic acid, lauric acid, and etc., were quantitated. The results showed that: 1) the contents of isovalerate, valeric acid, beta-methyl valeric acid, hexanoic acid, octanoic acid, nonanoic acid, lauric acid, oleic acid and myristic acid in the expanded tobacco reduced, while the contents of butyric acid and benzoic acid remarkably increased; 2) of the neutral components, isophorone and citronellol changed little, and the damascenone in expanded middle and lower leaves increased dramatically, the other fourteen components decreased with different degrees; the changes of thiazole, pyrrole, pyrazine and 2-ethyl-3-methyl-pyrazine correlated with the stalk position of tobacco leaves, and the other basic components reduced.