Ultraviolet photodetectors (UV PDs) have always been the research focus of semiconductor optoelectronic devices due to their wide application fields and diverse compositions. As one of the best-known n-type metal oxides in third-generation semiconductor electronic devices, ZnO nanostructures and their assembly with other materials have received extensive research. In this paper, the research progress of different types of ZnO UV PDs is reviewed, and the effects of different nanostructures on ZnO UV PDs are summarized in detail. In addition, physical effects such as piezoelectric photoelectric effect, pyroelectric effect, and three ways of heterojunction, noble metal local surface plasmon resonance enhancement and formation of ternary metal oxides on the performance of ZnO UV PDs were also investigated. The applications of these PDs in UV sensing, wearable devices, and optical communication are displayed. Finally, the possible opportunities and challenges for the future development of ZnO UV PDs are prospected.