Abstract: Progesterone，as a female hormone，plays a key role in human reproduction. Progesterone participates in regulating the oocyte development and maturation，ovulation，embry development and implantation, and pregnant maintenance. It was found that the inadequate progesterone could be one of causes of early abortion. Progesterone regulates the uterine receptivity for implantation and an optimal uterine environment for embryonic development. Progesterone also has positive effects on oocyte maturation and quality by regulating LH pulsatility and its receptor, and the development of dominant follicle. In addition，progesterone has a direct effect on the embryo development. In in vitro cultured embryos，progesterone supplementation increased the blastocyst rate and the implantation rate. The pharmacokinetics and pharmacodynamics of progesterone have been well studied, and synthetic progesterone has already been used in clinic. However, there were still much controversy in pathophysiological mechanisms of progesterone. This review summarizes the effects of progesterone on uterine endometrium，oocyte and embryo development.

Key words: Progesterone, Endometrium, Ovarian follicle, Oocytes, Embryonic development