Pig industry is an important component of animal husbandry industry in China.The domestic pig production mainly adopts self-breeding mode.The semen used in pig reproduction is usually fresh semen or diluted at room temperature， while semen cryopreservation technology can realize the long-term preservation of pig semen.Compared with cattle， mice and other species， the cryopreservation technology of pig semen needs to be further optimized and improved.In order to provide a theoretical reference for perfecting the freezing technique of pig semen and accelerating its large-scale application in pig production，this review summarized the development and main technological process of freezing and thawing of porcine semen， and the key factors affecting sperm motility after freezing and thawing， including semen collection， pre-cooling balance before freezing， addition of cryoprotectant agents， and cryopreservation methods.It also covered the physicochemical changes during the sperm cryopreservation process， such as physical structural damage， functional damage， and sperm anti-freezing mechanisms.Finally， the new methods to improve the cryopreservation efficiency of pig sperm were summarized and prospected， including nanotechnology treatment of semen and the study of cryopreservation biomarkers for sperm.