Oocyte in vitro maturation (IVM) is a technology with a long history that was established before IVF. Although it has been studied extensively, the efficiency of IVM has been poor for almost 30 years. In terms of the benefits of IVM, the efficiency and adoption of IVM are being improved by some notable improvements that have occurred in recent years. The establishment of biphasic IVM is the most important advancement in recent years. Biphasic IVM includes the pre-IVM culturing phase and IVM phase. The CNP-mediated pre-IVM culturing system is specifically tailored for non/minimally stimulated immature oocytes, and its efficiency has been shown. This is the most significant improvement made in recent decades in this area. In the clinic, IVM can be used for PCOS patients to avoid the occurrence of ovarian hyperstimulation syndrome (OHSS). Additionally, this method can solve the reproductive problems of some patients with special diseases (resistant ovary syndrome) that cannot be solved by IVF. In most fertility preservation procedures, oocytes in small antral follicles are lost. However, IVM has the ability to capture this kind of oocyte and save reproductive potential. IVM can be easily combined with fertility preservation strategies that have been applied in the clinic and improve the efficiency of fertility preservation. IVM is a useful and attractive technology and may be used widely worldwide in the near future.