Abstract: Ginkgolic acids were the allergen in Ginkgo seeds. Based on the results of single factor experiments, the orthogonal experiment were designed to optimize extraction conditions, and the compositions of ginkgolic acids in ginkgo seeds were detected by HPLC. The result indicated that the effect of factors on the extraction was in the order as follows, ethanol concentration, the most important one, and then ratio of material to liquid and extracting time. The optimum conditions defined at last were ethanol concentration 85 %, extraction time 12 h, ratio of material to liquid 1〖DK〗∶12.5. At this conditions, five ginkgolic acid monomers were detected in accordance with standard samples. Verification experiment suggested the extraction yield of ginkgolic acids reached 147.94 μg/g in dry weight, and the residual rate of ginkgolic acids was 2.19 % which was significant lower than the international standard. This method could offer a technological support for the detection of ginkgolic acids and quality control of ginkgo products.