With the development of multi-intelligence related technologies and distributed artificial intelligence, people have gradually applied drones to maritime search and rescue work. Maritime search and rescue requires high efficiency and short search time, which is difficult, and how to use UAVs for efficient and rapid maritime search and rescue has become a major concern. In this paper, based on the extended square search algorithm, the original algorithm is improved, and the probability function of target discovery is introduced to make the algorithm closer to the actual search and rescue situation. Finally, based on the MATLAB platform, this paper simulates the algorithm by writing a program, and studies the relationship between flight height, search pitch and search width overlap ratio and search time. The simulation results show that the flying height of the drone is inversely proportional to the search time, and the overlap ratio is proportional to the time. In the aspect of emergency data backhaul and communication, based on the original agreement of Beidou, the necessary transmission agreement keywords are added to facilitate the subsequent processing of the data.