Abstract: An ultraviolet image intensifier with response at 120～200nm is introduced. It is a vacuum optoelectronic device, with CsI directly evaporated on its MCP to form a reflective photocathode, with MgF2 as input window, and optical fiber as output window. The proximity focus structure is adopted for reducing dispersion and image distortion. It has high quantum efficiency and spatial resolution. Under the static condition, the spatial resolution of the ultraviolet image intensifier reaches 18Lp/mm, and it has great potentials in space science and astronomy observation.