Abstract: The granular cells share the same microenvironment with oocyte，and the "cross talk" by the gap junction between ovarian granular cells and oocyte regulates the growth and maturation of oocyte. The cumulus cells（CCs） also affected the fusion of gametes and the formation of the male pronucleus after ovulation. It was reported that the early embryos can overcome developmental block when they were co-cultured with CCs in vitro. With the development of assisted reproductive technology（ART），the prediction of transcriptional and protein expression of genome in CCs to the oocyte and embryo quality attached much more importance. This review discussed the effect of granular cells on maturation and fertilization of oocyte and development of embryo.

Key words: Cumulus cells, Ovary, Ovum, Oocytes, Embryonic development