Abstract: Special structure and composition are the key factors in determining electromagnetic wave absorption performance. In this study, spherical nanoparticles of carbon-coated silica (SiO₂@C) were synthesized by self-assembly technique, and then the hollow SiC spherical nanoparticles were prepared via high temperature heat-treatment. The morphology and phase of the samples were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD), and the electromagnetic parameters of the samples were tested by the vector network analyzer. The absorbing performance of SiC was regulated with the help of its dielectric loss and special microstructure, and the reflection loss (RL) of the samples with different coating thicknesses was calculated. The results showed that SiC nanoparticles produced by high temperature heat-treatment had been transformed from irregular shape to hollow spherical structure with the increase of carbon content in SiO₂@C. When the frequency was 14.06 GHz, the minimum reflection loss (RL_min) was -18.23 dB, and the effective absorption bandwidth (RL≤-10 dB) reached 5.34 GHz with a corresponding coating thickness of 1.9 mm, reflecting the characteristics of thin thickness and wide absorption band.