Abstract: In order to meet the different requirements of the industrial field, the polishing process of silicon carbide (SiC) ceramic with an ultra-smooth surface and no surface damage is studied, and a new method of ultraviolet photocatalytic-vibrated composite polishing is proposed. Based on the theory of ultraviolet photocatalytic reaction, the processing mechanism of photocatalytic-vibrated composite polishing was discussed, and different experiments were carried out. First, the methyl orange degradation experiment was carried out to study the dependence of the oxidative property of photocatalytic vibration composite polishing on vibration; then, the ultraviolet photocatalytic-vibrated composite polishing comparison experiment was carried out to study the polishing effect of SiC before and after vibration, and to verify the new polishing method’s effectiveness. The experimental results show that the strong oxidizing hydroxyl radicals generated by the photocatalytic reaction can oxidize high-hardness SiC into softer silica. The introduction of vibration not only reduces the agglomeration of the photocatalyst in the photocatalytic reaction, but also improves the uniformity of oxidation and removal, and thus improves the surface quality of SiC during polishing, and finally, a smooth surface with a roughness of 31–39 nm is obtained.