The relationship among growing process,drops and endogenous hormones contents on Ginkgo biloba seeds were studied. The results showed that the growing curve of seed is S shape. The period of seed expanding late from the beginning of May to the middle of July. There is a remarkable relation between seed growth and content of endogenous hormones in seeds. The contents of IAA,ZR and ABA are higher whereas GA 3 is lower in the period of flourishing florescence, then the content of IAA,ZR and ABA significantly decreased but GA 3 increases after pollination. In the period of seed expanding, the content of IAA and ZT gradually increases again, and reaches another peak at the beginning of July, then both of them steady decrease, but at the same time the content of ABA gradually increases until the seed ripe. In a word, the function of GA 3,IAA,ZR and ZT seem to prompt the seed growth, whereas ABA concerns with seed mature and drops. There are two times drops of Ginkgo biloba seeds. The drops are related to hormones.
