For the first time, SiC/reduced graphene oxide (rGO) core-shell nanowires used as highly effective, lightweight electromagnetic wave (EMW) absorbers can be successfully prepared by solution electrospinning with a subsequent annealing treatment under a nitrogen atmosphere. The nanowire is composed of cubic SiC nanocrystals with a turbostratic carbon and rGO nanosheet coating on its surface. The EMW absorption performance of the nanowire can be improved efficiently by tuning the GO dispersion volume of the electrospun solution. The nanowire was prepared from the electrospun solution with 1.0 mL of the GO dispersion and showed an optimum reflection loss value of -56.3 dB, and its effective absorption bandwidth can be <= 6.2 GHz covering the whole Ku band (12.2-18.0 GHz). It is found that the specific core-shell structure, defects and functional groups of carbon and rGO, and grain boundaries between the carbon cluster and SiC nanocrystals all play important roles in improving nanowire EMW absorption performance.