In recent years, UAV has been widely used in power inspection, forest protection, express delivery, agriculture, and many other fields, and hence UAV technology has developed rapidly. Unmanned Aerial Vehicles (UAVs) are characterized by large in quantity, small size, and high speed. It has become an inevitable trend for UAVs to enter non-isolated airspace, and conflict detection and resolution technology have also become the current focus of research. The improvement of conflict detection and resolution technology is of great significance to the safety and efficiency of UAV flights. This paper systematically reviews the current research results both at home and abroad, and summarizes problems in UAV conflict detection and resolution. The models of conflict detection and resolution are summarized, and the objectives and constraints of conflict resolution are described from the perspective of theoretical models. The common methods of conflict detection and resolution are summarized from the perspective of methodology. Finally, from the perspective of shortcomings in existing research, the paper envisions the future research trend and direction of UAV conflict detection and resolution.