Three flavonoid compounds, astragalin(1), isoquercitrin(2) and quercetin $3-O-{eta}-D-xylopyranosyl(1-2)-{eta}-D-glucopyranoside(3)$ isolated from the leaves of Eucommia ulmoides were identified and quantified by HPLC. All flavonoids were well separated on a ${mu}-Bondapak;C_{18}$ column with a mobile phase composed of THF-dioxane-MeOH-HOAc-5% $H_3PO_4-H_2O$(145 : 125 : 50 : 20 : 2 : 658). The contents of compound 1 in the methanol extract and n-butanol fraction were 0.09%(w/w) and 0.46%(w/w), of compound 2 were 0.08%(w/w) and 0.48%(w/w), and of compound 3 were 0.40%(w/w) and 1.22%(w/w), respectively.