In the event of a major natural disaster, communication equipment such as the base station in the area is vulnerable to damage, which is unable to meet the communication needs of the affected people. For this scenario, this study proposes a UAV-assisted file cooperative caching algorithm under the wireless mesh network architecture. Among them, the mesh router is the main cache device, the cache file block is used as the gene of cache strategy, and the genetic algorithm is used to implement file Cooperative Cache, which reduces the response delay of user request file, and achieves the purpose of emergency communication. UAV as the relay transmission node, takes the turning angle as the gene of trajectory planning, uses genetic algorithm to get the optimal relay position, assists the ground wireless mesh routing cache, and jointly provides file blocks for users. The simulation results show that the proposed algorithm can significantly reduce the average delay of users’ access to files and achieve the purpose of emergency communication.