This study develops a new ultraviolet (UV) photodetector composed of ZnO nanorods and CuCr_1-xMg_xO₂ films. First, ZnO nanorods were grown on CuCr_1－xMg_xO₂ films prepared by the sol-gel method under hydrothermal conditions. Then, the morphology, structure, and absorption properties of CuCr_1-xMg_xO₂/ZnO were characterized by scanning electron microscopy (SEM), an X-ray diffractometer (XRD), and a spectrophotometer. Finally, the UV photoelectric detection performance of CuCrO₂/ZnO and CuCr_1-xMg_xO₂/ZnO was investigated. The experimental results reveal that the detector has fast response; the photo-to-dark current ratio is about 2.6 times greater than that of CuCrO₂/ZnO at -10 V, and the device responsivity is 2.3 A/W higher than that of CuCrO₂/ZnO. The CuCr_1-xMg_xO₂/ZnO photodetector has excellent detection performance and the advantages of a simple preparation process, low cost, and mass production, which is an excellent photodetector with various applications in UV detection.