In the combustion process of aero-engines, excited-state free radicals such as OH*, NO*, and NH* emit faint self-chemiluminescence in the ultraviolet (UV) band, which changes rapidly with the progress of combustion. UV image intensifiers, featuring up to a million-fold electronic gain and nanosecond-level shutter speed, can capture the transient structure of the combustion flow field in the UV band, laying the foundation for the quantitative measurement and interpretation of the variation rules of combustion characteristics with multiple physical parameters. This paper summarizes the application of UV image intensifiers in optical diagnostics of aero-engine combustion, including passive optical diagnostic techniques for imaging OH* self-chemiluminescence, and active optical diagnostic techniques using laser excitation for OH imaging. Finally, in line with the requirements of high spatial and temporal resolution detection for new types of aero-engines, the development direction of UV image intensifiers in combustion diagnostics is pointed out.