In this paper, a simple preparative method for isolation and purification of ginkgolides A and B was developed. As starting material, a commercially available standardized ginkgo extract (EGb761, containing 24% flavonoid and 6% terpene trilactones) was used. After a pretreatment step, optimized by the uniform design method, the concentrated intermediate extract with high content of GA and GB (+90%) was separated into the individual terpenes by preparative liquid chromatography eluted with petroleum ether-ethylacetate. Analysis of products was carried out by means of HPLC-ELSD (evaporative light-scattering detector). The results show that ginkgolides A and B are obtained in higher yield and better purity.