Abstract: In order to investigate the reason causing some shortcomings associated with cut tobacco expanded by dry ice, such as short of flavor, higher irritation and unsatisfied mouth feeling, the sediment in gas phase and liquid phase carbon dioxide recovery towers in dry ice expanding systemwas analyzed by adsorption/thermal desorption-GC/MS.The results showed that there were many tobacco aroma components in the sediment, especially, neophytadiene, hexadecanoic acid and octadecanoic acid were at very high level.It indicated that the considerable losses of some aroma components in cut tobacco during expanding might be the main reason why the smoking quality of expanded tobacco became worse.