High-performance liquid chromatography (HPLC) was used to evaluate the influence of different variables affecting the hydrolysis of flavonoids in extract of Ginkgo biloba L.(EGb).The hydrolysis recovery was estimated and four kinds of quantiative methods were also been compared.The effects of concentration of HCl in methanol,time and methanol/H2O volume ratio can be interpreed by observing the variation of quantitative results.The acid-hydrolysis conditions optimized by using the orthogonal design method an...