Total flavonoid gly coside was isolated from Ginkgo biloba Linn.leaf tablet and determined by RP-HPLC using quercetin as external standard .4.6 mm ×100 mm Spherisorb ODS column, mobile phase:V( CH3OH) ∶V( 0.3 %H3PO4) =40∶60, flow rate:1 mL/min, detection :λ=370 nm.The sample was extracted with CH3OH by ultrasonic extraction and hydrolyzed with 25 % HCl, then sample solution was diluted accurately to 50 mL.This experiment showed that this is a simple, accurate and precise method with the result of fine linearity, average recovery is 101.1 % for quercetin, and RSD is 2 .44%