In order to further improve the performance of compound UAVs at high and low speed with heavy loading, a type of compound coaxial UAV with fixed wings and tail ducted-rotor thrusters was proposed to meet technology requirement. The lift and thrust aerodynamic characteristics were analyzed to get some relative characteristic and the aerodynamic coupling relationships between the fixed wings and tail propulsion system. And an optimization method based on hybrid Fuzzy-PSO (HFPSO) algorithm was proposed to obtain the optimal configuration plan that can reach the best aerodynamic performance without considering the coaxial architecture. The optimal configuration plan was finally obtained by applying the HFPSO method which also proves the method is effective and reasonable through comparison.