Abstract: With the vigorous development of modern agricultural aviation technology, higher requirements are put forward for the structure and performance of plant protection drones in the fields of pest control, aviation forest protection, seeding and fertilization.Aiming at the problems of small payload, poor redundancy, and low power of multi-rotor UAVs, this paper studies the UAV structure design, material selection, load application and other aspects.With strong power, large load, long endurance and light weight as the goal orientation, a design scheme of X-type coaxial twin-propeller plant protection UAV is proposed.First of all, build the UAV system and carry out the structural design according to the parameter requirements. Secondly, the whole machine is modeled and the static load check and dynamic modal analysis are carried out. Finally, a field flight test is carried out.The research results show that the design of the UAV has good functionality and reliability in terms of strength, rigidity and load capacity.It provides a theoretical basis and technical reference for the further optimization design of the coaxial twin-propeller large-load electric unmanned aerial vehicle.