The oocyte has a unique structure as a cell that undergoes meiosis and goes into a haploid state. The meiotic division covers the oocyte maturation process, during which the oocyte completes cytoplasmic and nuclear maturation. Meiosis encompasses the oocyte maturation process in which the oocyte completes cytoplasmic and nuclear maturation. In mammalian oocytes, meiosis stops at the diplotene stage of prophase in the embryonic stage; this stage is prophase I of meiosis and is defined as the germinal vesicle stage (GV). With puberty comes the cytoplasmic maturation of oocytes in each menstrual cycle. With the LH elevation, oocyte maturation first enters the meiotic metaphase I. Metaphase I occurs in Graafian follicles with the fragmentation of the germinal vesicle in the oocyte and the oocyte then enters the metaphase II with the expulsion of the first polar body. Oocyte nuclear maturation refers to modifications of nuclear components during meiosis. Fertilization can only occur in metaphase II oocytes. The meiosis 1 stage encompasses a long waiting period, and numerous studies on in vitro oocyte maturation are still ongoing, and improving this process covers a very important area in female infertility. Thus, uncovering the regulatory network in oocyte maturation and examining oocyte meiosis development not only illuminates how mammalian primates evolved, but also provides an overview of the cellular and molecular mechanism currently understood. In this review, especially epigenetic modification, the regulatory progress network of oocyte meiosis progression involving stopping meiosis and restarting meiosis by gonadotropins and oocyte maturation is summarized. Today, many laboratory methods have been developed for in vitro oocyte maturation by using various stimulants in tissue cultures. All these methods actually mimic in vivo oocyte maturation. The culture conditions to which the oocyte is exposed and various growth factors and chemicals added to the medium cause changes in the molecular mechanisms of the oocyte, leading to the transition to Metaphase II.