Abstract: AimTo establish a high performance liquid chromatographic method for determination of ginkgolic acids in Ginkgo biloba extract and its preparations. MethodsGinkgo biloba extract and its preparations were extracted with petroleum ether in Soxhlet apparatus, and then concentrated under vacuum. The ginkgolic acids were determined directly by HPLC,　and identified by LC/DAD/ESI/MS. The chromatographic column was Inertsil ODS-2; the mobile phase was methanol-3% aqueous acetic acid(92∶8);　the flow rate was 1.0 mL·min^-1; the column temperature was 40　℃; the detection wavelength was 310 nm. ResultsThere were six kinds of ginkgolic acid (C13∶0，C15∶1，C17∶2，C15∶0, C17∶1 and an unknown compound C17∶3 tentatively) in the Ginkgo biloba extract. The relative percentage content of ginkgolic acids C13∶0, C15∶1 and C17∶1 was above 94%. The content of ginkgolic acids in Ginkgo biloba extract containing high content ginkgolic acids was 1.12%, and RSD was 2.4%(N=5). The content of ginkgolic acids in one kind of EGb preparations (tablet) was 49.2　μg·g^-1, and RSD was 4.3%(N=5). The average recovery was 98.2%,　RSD was 2.6%(N=5). ConclusionThe method is accurate，　fast, simple, and can be used for determination of ginkgolic acids in Ginkgo biloba extract and its preparations.