The unmanned aerial vehicle (UAV) swarm warfare has become a hot spot in the military field, and the attention of various military powers in the world is increasing. With the deterioration of the battlefield environment and the continuous improvement of the autonomous ability of UAVs, unmanned swarms will become an important combat style for the application of UAV systems in the future. In order to deepen the understanding of UAV swarm warfare, this paper briefly describes the concept of UAV swarm warfare, its combat advantages, application styles and tactics, and analyzes the key technologies of UAV swarm warfare, such as AD hoc network communication, situation awareness, autonomous control and cooperative interaction. It provides a reference for future UAV cluster air attack penetration, urban attack and anti-terrorism operations.