Abstract: Melatonin is a kind of neuroendocrine hormone, which has a wide range of physiological effects. The synthesis and metabolism of melatonin in vivo were described in this paper. In addition, regulation of melatonin was reviewed, including maintaining glucose homeostasis, regulating activities, reproduction, antioxidant properties, molting and limb regeneration and circadian rhythm. Based on the above, some theoretical data were proposed for the future study of the mechanism about the effect of melatonin on the physiological function of crustaceans

Key words: melatonin, crustaceans, physiological regulation