Abstract: The orthogenal design was used to screen the extraction process of flavonoids in buckwheat. The optimum extactingconditions were 65% ethnol as solvent, raw material and solvent ratio 1∶15, extracting temperature 50～55℃, extracting time6h.The different materials were used to extracting flavonoids in the optimum extacting conditions, and the results showed thatbitter buck flour had the highest extrating rate of flavonoids, the the husk of bitter buck had less extracting rate, and the sweetbuck flour had the least extracting rate. The concertrated liquid of extracting flavones were isolated with thin layer chromatoyrophy,from which the similar structural substances of rutin and quercetin were gotten. There were flavonol, 5-hydroxylic flavone and2-hydroxylic flavone which were identified by color- reaction tests in the extracting liquid.

Key words: buckwheat, flavonoids, rutin, thin layer chrornatography