Carbon microspheres and C/TiO₂ microspheres with core/shell structure were successfully synthesized by hydrothermal method using glucose and Ti(SO₄)₂ as carbon source and titanium source,respectively.To improve the dielectric loss of these materials,the synthesized samples were carbonized at different temperatures under N₂ atmosphere.The structures and morphologies of the samples were characterized by X-ray diffraction,scanning electron microscopy and transmission electron microscopy.The relative complex permittivity of the composites was measured by a vector network analyzer in the frequency range of 2-18 GHz and their reflection losses were calculated.The results show that the carbon microspheres have high microwave dielectric loss.After the carbon microspheres were composited with TiO₂,the absorption peak migrated to low frequency under the same thickness.Particularly,the carbon and C/TiO₂ composites carbonized at 700℃ and 800℃ display excellent microwave absorption performances.The minimum reflection loss value arrives at -41.2 dB and -30.0 dB and the maximum band width less than -10 dB is 4.5 GHz and 4.2 GHz for C-700 and C/Ti-700 composites,respectively.