Abstract: Recent progress in microwave absorption materials stimulates the extensive exploration of rare earth oxide materials. Herein, we report the synthesis of a hollow sphere-based carbon material compounded with rare earth oxides. Hollow N-doped carbon nanospheres loaded ceria composites (H-NC@CeO₂) were designed and prepared by the template method, combined with in-situ coating, pyrolysis and chemical etching. By controlling the loading content of H-NC@CeO₂ and adjusting the impedance matching of the material, the H-NC@CeO₂/PS (polystyrene) composite exhibited a minimum reflection loss (RL) of −50.8 dB and an effective absorption bandwidth (EAB) of 4.64 GHz at a filler ratio of 20wt% and a thickness of 2 mm. In accordance with measured electromagnetic parameters, simulations using the high frequency structure simulator (HFSS) software were conducted to investigate the impact of the honeycomb structure on the electromagnetic wave performance of H-NC@CeO₂/PS. By calculating the surface electric field and the material’s bulk loss density, the mechanism of electromagnetic loss for the honeycomb structure was elaborated. A method for structural design and manufacturing of broadband absorbing devices was proposed and a broadband absorber with an EAB of 11.9 GHz was prepared. This study presents an innovative approach to designing advanced electromagnetic (EM) wave absorbing materials with broad absorption bandwidths.