Abstract: The steroid hormone, progesterone, plays a key role in diverse events associated with female reproduction. In humans and other vertebrates, the biological activity of progesterone is mediated by modulation of the transcriptional activ-ity of two progesterone receptors, PGR-A and PGR-B. This review introduced the structure, expression regulation and polymorphism of progesterone receptor gene. The relationship between progesterone receptor gene and reproductive func-tion was also discussed in mammals.