The application requirements of UAV (unmanned aerial vehicle) swarm communication payload technology based on FSO (Free Space Optical) were summarized, and the current status of FSO technology and application at home and abroad UAV payloads was discussed. The development prospect of the payload technology of UAV swarm based on FSO communication in high-speed mobile communication environment was also analyzed. Furthermore, a profound analysis on the key technologies in FSO communication links applied to UAV swarm was conducted. Predictably, FSO-based communication payload will be used widely for wide-bandwidth communication networking of UAV swarm in the future.