Abstract: In insect, vitellogenesis is a rather complicated process, which is affected by various external factors(eclosion, nutrition, mating, temperature etc.) and internal factors(EDNH, JH, ecdysone, OOSH etc.). According to the mode of hormone regulation of Vg synthesis, insects can be divided into three groups. In the first group, represented by Locusta migratoria, Rhodnius prolixus, Coccinella septempunctata and cockroaches, JH is the only known hormone regulating Vg gene expression. In the second group, mainly Diptera (Aedes aegypti, Musca domestica, and Drosophila melanogaster etc.), JH, ecdysone, EDNH and the midgut neurosecretory system are involved in the regulation of Vg synthesis. Ecdysone is the key hormonewhich regulates Vg synthesis in the fat body, and JH increases the competence of the fat body. In the third group, Lepidoptera, vitellogenesis is initiated either in pharate adults or in adults after eclosion, and both JH and ecdysone or either of the two hormones may be involved.