Protein kinase C is an important family of serine/threorine protein kinase. In this experiment the possible roles of PKC in meiotic maturation, fertilization and egg activation were studied in mouse oocytes. Two isoforms of PKC, PKC alpha and beta 1, were localized in mouse oocytes. PKC activator PMA inhibited the resumption of meiosis in oocytes at GV stage, whose effect could be overcomed by PKC inhibitor calphostin C, neither the phospholipase C inhibitor U73122 nor the PKC delta-specific inhibitor rottlerin. The result of Western bolt indicates that both PKC alpha and beta 1 express stably during oocyte development. The translocation of PKCs and cortical granule exocytosis were observed by confocal microscopy. The results show that PKC alpha translocate from the cytoplasm to the membrane after fertilization or drug-stimulation, accompanied by CG exocytosis. This fact suggested that PKC alpha might be involved in the regulation of cortical reaction in mouse oocytes. Roles of PLC gamma in mouse oocyte during fertilization and localization of PKCs in mouse ovary were also investigated in this experiment. The result suggested that there did not exist a feedback regulation of PLC gamma on PKC during fertilization.