Abstract: In order to determine the formation mechanism of glycoside aroma precursors in tobacco leaves at later growth stage and to improve the aroma quality of tobacco leaves, the variations of aglycon aroma components and their contents in tobacco leaves of same cultivar under the same cultivation conditions from different producing areas(Neixiang and Baofeng in Henan Province, Yuxi and Puer in Yunnan Province, and Huili in Sichuan Province) were analyzed by SDE-GC/MS method. The results showed that:1) The aglycon aroma components detected in tobacco leaves from 5 areas were the same, with 28 chemical types in total, including 4 aldehydes, 17 ketones, 5 alcohols, 1 phenol and 1 lactone. 2)The total content of all the aglycon aroma components from 5 areas all increased with the increase of leaf maturity, increasing from the 55th day after transplantation and peaked on the 85th day, then decreased slightly after 100 days. 3)At later growth stage, the total content of all aglycon aroma components in leaves from Neixiang and Baofeng was higher than that from Huili, Yuxi and Puer. 4) The aglycon aroma contents were in the order of:aldehydes > ketones > alcohols > others (lactone and phenol) in leaves from Baofeng, Yuxi, Puer and Huili, which were ketones > aldehydes > alcohols > others in leaves from Neixiang. The content variations of all aglycon aroma components were the same as that of their total content.