Tobacco, as an important cash crop and model plant, has been studied and explored in various aspects. In China, Yunyan 87 was recognized as a flue-cured tobacco variety and had been widely concerned due to its excellent product quality characteristics. The quality of tobacco products depends on the compound collection of tobacco leaves, including pigments, carbohydrates, amino acids, polyphenols and alkaloids. Present study investigated tobacco seedlings, with the assistant of the untargeted metabonomic technology and the label-free proteomic technology to analyze metabolites and proteins differences in leaf, stem, and root groups respectively. From 298 metabolites and 4993 proteins obtained, there were significant differences in both primary and secondary metabolism involved aroma precursors biosynthesis in seedling tobacco leaves, stems, and roots, such as carbohydrate metabolism, energy metabolism, and amino acid biosynthesis, and secondary metabolism phenylpropanoids, flavonoids and alkaloid biosynthesis in this study. Especially alkaloids metabolites identification results showed nornicotine, anatabine, anatalline, and myosmine, were significantly higher in tobacco roots than in leaves, and stems at seedling stage.