Abstract: Using SiC nanowires (SiC_NWs) as the substrate, reflux–annealing and electrodeposition–carbonization were sequentially applied to integrate SiC nanowires with magnetic Fe₃O₄ nanoparticles and amorphous nitrogen-doped carbon (NC) for the fabrication of SiC_NWs@Fe₃O₄@NC nanocomposite. Comprehensive testing and characterization of this product provided valuable insights into the impact of structural and composition changes on its electromagnetic wave absorption performances. The optimized SiC_NWs@Fe₃O₄@NC nanocomposite, which has 30wt% filler content and a corresponding thickness of 2.03 mm, demonstrates exceptional performance with the minimum reflection loss (RL_min) of −53.69 dB at 11.04 GHz and effective absorption bandwidth (EAB) of 4.4 GHz. The synergistic effects of the enhanced nanocomposite on electromagnetic wave absorption were thoroughly elucidated using the theories of multiple scattering, polarization relaxation, hysteresis loss, and eddy current loss. Furthermore, a multicomponent electromagnetic wave attenuation model was established, providing valuable insight into the design of novel absorbing materials and the enhancement of their absorption performances. This research demonstrated the significant potential of the SiC_NWs@Fe₃O₄@NC nanocomposite as a highly efficient electromagnetic wave-absorbing material with potential applications in various fields, such as stealth technology and microwave absorption.