Propeller is the crucial component of the fixed-wing aircraft. It provides thrust for fixed-wing aircrafts and has a great influence on the aerodynamic performance and carrying capacity of fixed-wing aircraft. For motor-driven micro-sized fixed-wing transport aircraft, the propeller needs to cooperate well with the motor to achieve high propulsion efficiency. In order to obtain the optimal design of propeller, experimental and numerical investigation was carried out and compared with three kinds of propeller. The tailor-designed propeller was proposed under specific conditions. Tailor-designed propeller better fits with the motor in the flight of the aircraft, improving the efficiency of the propellers, and increasing the carrying capacity of the aircraft. According to the characteristics and working conditions of the aircraft and the working characteristics of the motor obtained from the experiment, the aerodynamic shape of the propeller is initially designed based on the leaf theory and Betz conditions, then the parameters are continuously adjusted based on the numerical simulation results, and the results with the best performance are selected as the final result. Comparing the numerical simulation results and experimental results of tailor-made propellers and existing propellers under design conditions, the results show that, with the same power absorbed by the motor, the tailor-made propeller can provide greater thrust. The increase in thrust means that the aircraft can overcome greater resistance and generate greater lift, which improves the carrying capacity of aircraft. Numerical simulation and test flight methods were used to explore the impact of thrust improvement on aircraft lift and carrying capacity.