With the improvement of automation and intelligence degree of unmanned aerial vehicle, its application scenarios and service scope continue to expand. The UAV system is complex and the task environment is changeable, which poses new challenges to its safety and reliability. Fault prediction and Health management (PHM) technology can effectively reduce the risk of mission interruption caused by faults, and improve the quality of UAV mission throughout its life cycle. Firstly, the framework of UAV PHM technology is proposed based on the basic concepts of UAV and PHM technology, and then the research status of UAV fault diagnosis and fault prediction technology is analyzed and summarized. Finally, the challenges of UAV fault diagnosis and prediction technology are discussed. In addition, the development trend of UAV PHM technology is summarized from four aspects: failure mechanism basis, condition monitoring technology, fault model construction and intelligent technology application, aiming to provide certain reference for the research and development of the new generation of UAV PHM technology.