Abstract: Objective: To compare the contents of nutrition components and active ingredient between common and tartary buckwheat.Methods: The mean contents of basic components ( moisture and ash) , nutritional compositions ( amino acid, fatty acid, starch and protein) and functional active ingredient ( flavonoids, polyphenols and rutin) in 7kinds of tartary buckwheat and 6 kinds of common buckwheat were determined. Results: The moisture content of common buckwheat was significantly higher and ash content was significantly lower than that of tartary buckwheat ( p < 0.05) . There were no significant differences in the contents and distributions of fatty acid and proteins, although they were abundant in both of buckwheat ( p > 0.05) . Flavonoids and polyphenols contents in tartary buckwheat were 125.33, 107.24 mg / g and were 15.23, 2.68 times of that in common buckwheat respectively.Tartary buckwheat was also abundant in other active ingredient such as rutin, quercetin, isoquercetin and kaempferol.While the oligosaccharide content of common buckwheat, including stachyose, saccharose and raffinose were significantly higher than that of tartary buckwheat ( p < 0.05) . Conclusion: The content of functional components, such as flavonoids, polyphenols and oligosaccharides showed significant difference but nutrition components like amino acid, fatty acid and starch had no significant difference between common and tartary buckwheat.