Abstract: Osmoregulation involves many aspects of physiological function in crustacean. Crustacean species exhibit almost all possible patterns of osmotic regulation and they are widely distributed in most of known biotopes. With the changes of liquid environment , the structure and function of the osmoregulation organs (such as gills , antennary glands) ,haemolymph osmotic pressure and ionic transport will turn to maintain the well2balanced metabolism , which are under the neuroendocrine regulation. The current research status of physiological mechanism of crustacean osmoregulation was reviewed in the following aspects : 1) Structure and function of gills and antennal glands (maxillary glands) . The gills are very important organs and play a prominenet role in osmoregulation; 2) Regulation of ion transport in branchial epithelium. Ion transport enzymes (Na 2K 2ATPase , V2ATPase , HCO322ATPase and carbonicanhydrase) stimulated by bioamines and cAMP may participate in the ion transport of branchial epithelium in crustacean; 3) Haemolymph composition and osmoregulation. Haemolymph concentration of ion and free amino acid accompanied by metabolites of blood can contribute to the most of haemolymph osmotic pressure; 4) Neuroendocrine control. Many neuropeptides may regulate the osmotic pressure of haemolymph and proteinsases activity of epithelial gill cells. Bioamines , cAMP and CaM have been proved to stimulate the uptake of Na and transport of Cl .