Unmanned Aerial Vehicles(UAV) are increasingly widely used in military, commercial and civil fields. With the increase of the number of Guavas, the impact on security, privacy and public interests has also been increasingly valued. Therefore, it is more and more important to study the target detection technology for UAV group. At present, a number of research work related to the detection of UAV swarm targets has been carried out at home and abroad. In this paper, the research status and challenges of UAV group target detection are studied. Then, aiming at these challenges, the types of UAV group target detection architecture technology are discussed. In view of the difficulty of centralized and single means to meet the needs of UAV group fine perception and situation assessment, the air-ground joint multi-domain detection architecture for UAV group targets is provided, which specifically includes networking radar, distributed spectrum passive monitoring equipment, mobile multi-spectral sensing equipment, mobile spectrum monitoring equipment. Combining the advantages of different sensing methods in different distances, different directions, different granularity and other dimensions, it breaks through the limitations of single-domain detection through cascade, collaboration and fusion. Finally, the key technologies are analyzed and summarized.