The tactical performance and advantages of unmanned aerial vehicle (UAV) system will play an increasingly important role in future high-tech warfare and civil aviation. However, due to the different characteristics of manned and unmanned aerial vehicle flight accidents, the safety analysis and management measures of manned aerial vehicle are not suitable for UAV system. Therefore, the safety and hazard analysis of UAV system is carried out to construct the UAV security management framework. Firstly, according to the statistical analysis of UAV system flight accidents, the characteristics of UAV system accidents are concluded. And then the safety of UAV system is defined, the classification of severity and its corresponding acceptability for UAV system are presented. Finally, hazard analysis is carried out from design, crew training and operation fields.