Abstract: Aerodynamic shape optimization constitutes a critical step in Unmanned Aerial Vehicle (UAV) design, with the lift-to-drag ratio (L/D) serving as a pivotal metric for evaluating aerodynamic efficiency and flight performance. In this paper, the aerodynamic shape of a modular UAV is optimized with the objective of maximizing the L/D for both the single-body UAV and the three-body combined UAV, respectively. A comprehensive optimization method is proposed that integrates airfoil optimization and UAV configuration parameter optimization. Profile shape optimization for a modular UAV is implemented via airfoil design optimization. Using the Hicks-Henne function for airfoil parameterization, the airfoil geometry is optimized by integrating computational fluid dynamics (CFD) with design of experiments (DOE) methods. Optimization results reveal a 14% increase in L/D under specified operating conditions, which validates the effectiveness of the proposed strategy for achieving enhanced aerodynamic performance and optimal configuration design of composite UAVs. The optimization method is computationally efficient and practically convenient, significantly shortening the overall design cycle.