Due to its unique physical, chemical, and electrical properties and the feasibility of growing in the form of thin films, diamond is an ideal material for manufacturing reliable and long-life micro-electromechanical/nanoelectromechanical systems (MEMS/NEMS). In recent years, the development of chemical vapor deposition of diamond thin film has promoted the application of diamond in MEMS and realized a new era of development of diamond-based MEMS and NEMS. However, due to the difficulty in precise processing, diamond has not yet been widely applied in NEMS/MEMS. In this article,the current research progress of diamond-based MEMS is introduced, as well as the processing methods of diamond-based MEMS system. The prospect of diamond application in MEMS is proposed.