Abstract: Flavonoids was extracted from the foot of the ginkgoes by the method of soaking and backwater.The content of flavonoids determined with a spectrophoto meter of model 721 was 6.89%.In the root of ginkgoes,the content of quercetin accounted 1.24%.It was determined by high performance liquid chromatography.The optimal detection wave length settled by ultiaviolet and visible spectrophoto metry.

Key words: spectrophoto meter, high performance liquid chromatograph flavonoids, quercetin, the root of the ginkgoes