Nanodiamonds have shown excellent mechanical properties, thermal conductivity, biocompatibility and structural tunability, and have been widely demonstrated their application in the fields of composite materials, electrochemistry, catalysis, medicine and so on. In industry, the mass production of nanodiamonds by detonation method provides a foundation for their application. Due to the complex surface structure of nanodiamonds, precise control is required to achieve the target performance and the research on surface functionalization is of great practical significance. This review firstly introduces various surface modification methods of nanodiamonds, then focuses on the impact of surface functionalization research on the application of nanodiamonds in mechanical properties, catalytic properties and biomedical fields, and finally prospects the future research direction of nanodiamonds.