A novel SiC/C_f composite with SiC array modified coating was prepared by electroless plating combined with high temperature sintering using glucose, Si powder and carbon fiber as raw materials. The phase composition, microstructure and absorbing properties of SiC/C_f composites were characterized by different methods. The results show that the surface of the carbon fiber is coated with a large amount of SiC arrays, which grows outward on the surface of the carbon fiber. The SiC arrays are uniformly distributed and approximately 1.4 μm in height. When the thickness of SiC/C_f composite is about 1-2 mm, with the thickness increasing, the minimum reflection loss (RL_min) moves from high frequency to low frequency. When the absorber thickness is 1.8 mm, the RL_min reaches -40.653 dB at 8.31 GHz and the effective absorption bandwidth (RL < -10 dB) is 1.11 GHz. When the thickness is 1.5 mm, the minimum effective absorption bandwidth can reach 2.42 GHz. Additionally, the RL_min is less than -20 dB when the absorber thickness ranges from 1.3 to 1.8 mm. This new SiC/C_f composite modified by SiC array is expected to be a lightweight and efficient electromagnetic absorbing material.