Voice conversion usually refers to the process of modifying and transforming the personalized features of a person’s voice to make it sound like another person’s voice while keeping the linguistic information unchanged. In recent years, with the rapid development of information processing and machine learning, the technology of voice conversion has also achieved great progress. On the basis of introducing the basic concepts of voice conversion, the typical models and methods of voice conversion researched in recent years are summarized in this paper, the key technologies of voice conversion are reviewed, the main application scenarios of voice conversion technology are listed, and some technical problems still existing in voice conversion at present are briefly introduced. Finally, the prospects for the directions of the research and development of voice conversion are given.