As a widely used type of aircraft, unmanned aerial vehicles (UAVs) have strict requirements for lightweight and high-strength structures, and topology optimization techniques can meet these design requirements. By setting reasonable design domains, boundary conditions, and load conditions, and utilizing mathematical modeling and numerical calculation methods, topology optimization can optimize the shape and material distribution of structures while ensuring sufficient stiffness and strength, thereby achieving lightweight design of UAVs. This work proposes a structural design framework for UAVs based on large-scale paralleled topology optimization. First, a user-friendly interface is developed to realize the transformation from face-based mesh to volumetric mesh and convenient setting of load and boundary conditions for topology optimization. Then, a parallel accelerated large-scale topology optimization is performed to find the optimal material distribution under complex loading conditions. Finally, an interactive structural reconstruction method is presented to realize efficient transformation from optimized structure to an editable skeleton-based structure. The proposed structural design framework is validated by an application case of designing the reinforcing structures for a fixed-wing UAV airframe using 10 million scale elements.