The invention provides a photoconductive ultraviolet detector and a manufacturing method thereof. The photoconductive ultraviolet detector is composed of an insulating substrate, an ultraviolet sensitive film, metal electrodes and graphene transparent interdigitated electrodes sequentially from bottom to top. The insulating substrate can be a quartz glass sheet or a silicon wafer, wherein an insulating medium such as silicon oxide or silicon nitride is grown or deposited on the surface of the silicon wafer. The ultraviolet sensitive film is made of a film material chosen from gallium nitride, aluminum-doped gallium nitride, zinc oxide, magnesium-doped zinc oxide, silicon carbide and diamond. The strip-shaped metal electrodes are made of gold or platinum. The graphene transparent interdigitated electrodes cover the ultraviolet sensitive film and the metal electrodes. By adopting the graphene transparent interdigitated electrodes instead of metal interdigitated electrodes, the ultraviolet radiation transmittance of the detector is high, and the performance of the device is improved.