Utilizing the Multiple Reference Frame model method, this study investigated the impact of a diffuser on the hovering efficiency and thrust of various components of a ducted propeller. By solving the RANS equation and analyzing the aerodynamic characteristics and flow field distribution characteristics of three different propeller configurations (non-diffuser ducted propeller, ordinary ducted diffuser, and isolated propeller), the research findings revealed interesting insights. The results indicate that the hovering performance of the non-diffuser ducted propeller is slightly inferior to that of the ordinary ducted propeller, yet still outperforms the isolated propeller. Additionally, the ducted thrust of the non-diffuser ducted propeller was found to be lower compared to the ordinary ducted propeller, while the propeller thrust of the non-diffuser ducted propeller surpasses that of the ordinary ducted propeller.