Abstract: hCG, a glycoprotein hormone produced by placental syncytiotrophoblast, is a signal molecules of pregnancy. Though hCG has similar structure and same receptor with LH, hCG has higher binding affinity with receptor and longer half-life period when compared with LH. So, exogenous hCG is often used to promote follicular maturation and to support the luteal phase. Besides those effects, hCG is beneficial to follicular raise, growth and development, and to embryonic implantation. In a word, hCG plays an important role in ART clinic and basic research.

Key words: Chorionic gonadotropin, Reproductive techniques, assisted, Ovarian follicle, Embryo implantation