The present invention discloses a dogbane total flavone and its contained effective component hyperin, isoquercitrin and quercetin, etc. The present inention also discloses a preparation method of dogbane total flavone. Said method includes the following steps: using Chinese medicinal material dogbane as raw material, adding ethyl alcohol to make extraction, recovering ethyl alcohol to obtain alcoholic extract, dissolving said extract in boiling water, filtering, feeding the supernatant fluid into polyamide column, using water to make elution, then using ethyl alcohol to make elution, collecting eluent, recovering ethyl alcohol, vacuum drying to obtain dried dried extract, using colorimetry to determine dogbane total flavone content, and using said dried extract as medicinal effective component. Said dogbane total flavone content is up to above 50%. |