To revitalize rural areas, technology must take the lead. Only by modernizing agriculture can China achieve complete modernization. In recent years, SAGIN (Space-Air-Ground Integrated Network) has received widespread attention from academia and industry, and can be applied in many practical fields such as global surveying, intelligent transportation systems, military missions, and more. As an information carrier for aerial platforms, the deployment strategy of agricultural and forestry plant protection drones is crucial to the performance of the system. This paper mainly studies how to establish a mathematical model for maximizing energy efficiency of unmanned aerial vehicles (UAVs) based on SAGIN swarm intelligence technology, under the constraints of energy and user rate, by jointly optimizing launch power and flight trajectory.