In this paper, we have studied on the absorbing properties of three different types of SiC absorbers such as ultra-fine SiC, SiC whisker and nanometer SiC. Electromagnetic parameters of the three types of SiC were tested in the frequency range of 2~18GHz. Both the real and imaginary parts of complex permittivity of nanometer SiC are higher than that of others. The attenuation constant of nanometer SiC is higher than that of ultra-fine SiC and SiC whisker, increasing from 93.7 to 766.5 with increasing frequency. The minimum reflection loss of -5.53 dB was obtained at 9.72 GHz for the nanometer SiC. The nanometer SiC suggests a better capacity of dielectric loss in microwave range than that of ultra-fine SiC and SiC whisker.