Influence of carbon content on surface quality of solid-state sintered SiC ceramics with nearly full density was first investigated. Comparison study was carried out with varying carbon contents of 2, 3, and 6 wt%, respectively. Investigation on surface morphology using atomic force microscope reveals that residual carbon presents as protuberances on the polished surface. The surface quality of the polished samples was improved by decreasing carbon content, and with 2 wt% carbon, the surface quality can reach 0.7 nm rms surface roughness after polishing. It offers a material-design approach to improve surface quality of solid-state sintered SiC ceramics.