Vitrified bonded SiC composite ceramics were prepared using a simple powder blending, forming, and sintering process. The effect of SiC particle size on the mechanical and dielectric properties of vitrified bonded SiC composite ceramics was investigated. Vitrified bonds wet and coat SiC particles during sintering and form continuous bonding networks upon cooling. The vitrified bonds render the ceramics high flexural strength and act as impedance mismatching modification layer between SiC particles and air. With varying SiC particle size, the microstructure, and properties of the vitrified bonded SiC composite ceramics change accordingly and at 7 mu m, it reaches optimal microstructure, a highest flexural strength of 67.85 MPa and highest reflection loss. However, the dielectric loss of composite ceramics decreases as the SiC particle size increases.