The ducted propeller refers to the propeller surrounded by a duct. Compared with ordinary propellers, it has the characteristics of high aerodynamic efficiency and good safety performance. The vertical takeoff and landing fixed-wing aircraft combines the advantages of both fixed-wing unmanned aerial vehicles (UAVs) and rotorcraft UAVs, avoiding their respective disadvantages. It can take off and land vertically, and has the advantages of fixed-wing fast flight and efficient cruising at the same time, which can effectively expand the scope of UAVs’ combat mission execution and improve the flexibility of battlefield use. In this paper, an aerodynamic configuration optimization design is carried out for a vertical takeoff and landing fixed-wing aircraft. The two-dimensional duct is optimized, and finally, a two-dimensional duct profile shape with better lift-drag characteristics is obtained, and this optimized profile shape is used as the basis for three-dimensional optimization. Subsequently, the dihedral angle of the wing is optimized for the three-dimensional aerodynamic configuration, which improves the aerodynamic performance of the entire aircraft and meets the requirements of the overall design of the aircraft.