Abstract: Since the discovery of follistatin（FST）in follicular fluid of pigs and cattle in the 1980s，studies on FST have never ceased and various functionalities of FST have been identified by in vivo and in vitro experiments. FST as a secretory protein is present and secreted in various tissues and organs of mammals. It plays a key role in hormone regulation，energy metabolism and muscle adipose tissue proliferation and differentiation. As FST is found from the gonadal，people have clearly studied FST regulating sex hormone secretion and signal transmission and promoting oocyte maturation and embryonic development，and the animal experiments with a number of species were carried out to identify the mechanism of action. FST as an inhibitor of TGF-β superfamily can be specifically combined with a member of myosin（MST），which produces antagonism and promotes muscle proliferation，differentiation and expansion. Brown fat as an important metabolic tissue in mammals has been a hot spot. FST has been found to promote brown adipose differentiation and induce white fat browning in recent years，which has been validated in cell experiments and mouse experiments. This review introduces FST and its important functions as well as the action mechanisms and development prospects of varied function，aiming at paving the basis for further research and development of FST.

Key words: follistatin, myostatin, brown adipose tissue