Abstract: Five ginkgolic acids in ginkgo biloba L. were extracted from the sample with methanol under refluxing. The extract was made up to 25 mL and an aliquot of 2 mL was taken and purified by extraction with n-hexane from a solution containing diatomite at pH 2-3. The supernatant was taken and evaporated to dryness rotationally under vacuum. The residue was dissolved with 2 mL of methanol, and 20 μL of the solution were introduced for RP-HPLC analysis by separation on Waters Symmetry-C18 column with the mobile phase of CH3OH-H2O (88+12, containing φ 5% of HOAc). Contents of the 5 acids were determined by DAD at the wavelength of 310 nm. Linear relationships between values of peak area and mass concentration of 5 ginkgolic acids were kept in the definite range, with detection limit (3S/N) in the range of 0.26-1.37 mg·L-1. The value of average recovery found by standard addition method was 99.2%, with value of RSD (n=5) of 6.83%.