Abstract: Based on the application requirements of aquatic-aerial amphibious vehicles, a ducted fan propeller is designed from three aspects:theoretical calculation, simulation and experiment. By theoretical calculation, the fan and motor operating curves both in the air and underwater are analyzed, and a forecast model of the thrust coefficients and torque coefficients of the fan is put forward. By selecting the appropriate estimation parameters, the design parameters of the fan and the motor are obtained. According to the theoretical calculation results, a suitable combination of fan and motor is selected. In order to verify the authenticity of the theoretical calculation, some CFD (computational fluid dynamics) simulations in the fan-only condition are carried out. And in order to analyze the real running performance, some CFD simulations of the whole surface structures of the ducted fan propeller are performed as well. Finally, experiments are carried out on the ducted fan propeller with the proposed combination manner, and the measured thrust coefficients underwater and in the air are 1.47×10^-4 and 2.48×10^-4 respectively, and the relative error with respect to the simulation results is about 10.9% and 3.6%, which are close to the uncertainty of the experiment. The thrust in the air can be greater than 55 N, and underwater thrust can be greater than 245 N, which can meet the requirements.