Abstract: The main purpose of this study was to explore the key aroma in flue-cured tobacco leaves, and to classify different ecological regions tobacco based on this. Seventeen aroma were analyzed by N-hexane solvent extraction and liquid chromatography-gas chromatography-mass spectrometry (LC-GC-MS) method with 115 flue-cured tobacco samples collected from 25 sampling points in six ecological regions. Principal component analysis and cluster analysis were conducted on the determination results of aroma. Results showed that the contents of fourteen aroma components were significantly different among flue-cured tobacco leaves from different ecological regions. Moreover, eight aroma components including megastigmatrienonel in flue-cured tobacco leaves of mountainous areas of central Guizhou were significantly higher than the other regions. Principal component analysis suggested that the key of aroma components in flue-cured tobacco leaves included megastigmatrienonel, solanone and norsolandione. The highest score of principal component was from the mountainous areas of central Guizhou, while the lowest score was from Yunnan, Guizhou plateau production areas. Using principal component-cluster analysis method based on the contents of aroma components in flue-cured tobacco leaves, the six ecological regions tobacco in this study could be divided into three clusters, with the first one represented by the mountainous areas of central Guizhou, the second one represented by the mountainous areas of Qinba, and the third one represented by the mountainous areas of Wuling. In addition, the sampling points of Shandong production areas, Northeast production areas and Yunnan, Guizhou plateau production areas belonged to the second and third cluster respectively. Aroma components can be used in evaluating and classification of flue-cured tobacco from different ecological regions.