Abstract: In order to explore the differences in quality characteristics of toasted tobacco leaves of core parents of high-quality flue-cured tobacco, we selected 7 commonly used breeding parents, compared and analyzed the conventional chemical components, odorant substances and sensory quality of the toasted tobacco leaves. The results showed that the chlorine content varied greatly among different varieties; the ratio of two sugars and the potassium to chlorine ratio were all within the suitable range of high-quality flue-cured tobacco; the nitrogen-alkali ratio was higher in all varieties except NC82 and Dabaijin599, which were within the suitable range. The contents of carotenoid degradation products, chlorophyll degradation products, browning reaction products and other aroma substances were the highest in Honghuadajinyuan, and the contents of phenylalanine-like degradation products and cembrane-like degradation products were the highest in Gexin3. Based on cluster analysis we could divide the 7 flue-cured tobacco varieties into 3 categories: G28, K326, Xiaohuangjin1025, NC82 and Gexin3 belonged to one category, and Dabaijin599 and Honghuadajinyuan belonged to two separate categories. After factor analysis and OPLS-DA analysis, 17 differential metabolites were identified, with the contents of β-Ionone, Dihydroactinolactone, 2,4-Heptadienal, (E,E)-1 and β-Ionone-5,6-epoxyde breing higher in Honghuadajinyuan, and the contents of Megastigmatrienone-1, Megastigmatrienone-2, Megastigmatrienone-3 and Megastigmatrienone-4 being higher in NC82 and Honghuadajinyuan, the content of 2-Formylpyrrole being higher in Xiaohuangjin1025 and Gexin3, the content of Pyranone being higher in Xiaohuangjin1025, the content of Norsoladione beinghigher in Gexin3, the content of Solanone being higher in NC82, G28 and Gexin3. The characteristics of aromatic substances in different varieties are different, which can provide guidance for aroma breeding.