The operating conditions in several key links for analysis of contents of flavonoids from the leaves of Ginkgo biloba by high performance liquid chromatography(HPLC) have been investigated. They included the composition of hydrolysis solution, the temperature and the time of the hydrolysis. The possibility of using only one standard of quereetin to evaluate the contents of three flavonoids, i.e. quercetin, kaempferol and isorhamnetin at a wavelength of 370nm was demonstrated. The selectedhydrolysis conditio...