Abstract: Variation rules of flavonoid content in leaves of young Ginkgo biloba tree influenced by altitudes and seasons were studied in this paper,and the affecting mechanisms of environmental factors were also discussed.Distinct variations of flavonoid content in leaves took place in the different growths period of leaves at the same position conditions.The distinctive ecological condition of higher altitude areas promoted the accumulation of flavonoids.Select of optimum time for leaf picking may improve the officinal quality of Ginkgo biloba leaves.