[Objective]To optimize the extraction process of flavonoids from Hedyotis diffusa and identify its structure,so as to provide reference for the further development of the medicinal value of Hedyotis diffusa. [Method] By employing single factor test and orthogonal test,the extraction process of flavonoids from Hedyotis diffusa was opitimized. Its chemical structure was identified by UV and IR analysis. [Result] The influencing order of each factor on the yield of flavonoids was determined to be extraction te...