The ducted propeller designed for a single working condition usually cannot meet the high efficiency requirements of vertical take-off and landing aircraft under multi-working conditions. The key to the multi-working condition design of the ducted propeller based on the blade element momentum theory lies in the calculation of the propeller thrust ratio and the correction of the inflow velocity under different working conditions. In the absence of propeller geometry, the momentum source method is used to estimate the duct thrust, and a method for correcting the inflow velocity is proposed. Based on the principle of minimum energy loss, the propeller geometry is established and the multiple reference frames method is used for coupled CFD（Computational Fluid Dynamics） correction to obtain the relationship between chord length and twist angle, propeller thrust ratio and corrected inflow velocity under a single working condition. By changing the design lift coefficient and rotational speed, the chord length and twist angle of the ducted propeller can be matched under different working conditions. The design results show that the momentum source method may calculate a large proportion of the duct thrust, and the method of correcting inflow velocity can reduce the computational cost of coupled CFD solutions under the same working conditions. Multi-working condition optimization can effectively improve the overall efficiency of the ducted propeller.