Ni?SiC composite coatings were successfully deposited on interior surfaces of cylinders by circulating-solution electrodeposition (CSD) technique on a newly-designed composite electroplating apparatus. The circulating solution agitation was effective to improve the dispersibility of SiC particles. The morphology, microstructure, hardness and tribological performances of Ni?SiC composite coatings varying SiC content were studied. Results showed that the dominant wear mechamism was oxidative wear, accompanied by abrasive wear. The friction coefficient and wear rate decreased with increasing SiC content. The excellent wear resistance was attributed to the existence of (111) growth twins, the improved hardness, the protections from NiO layer and SiC reinforcements, and the friction-induced microstructure changes underneath the tribo-surface. The protective capability of NiO layer and micro-SiC particles were discussed in detail.