Due to its excellent physical properties, diamond is regarded as a next-generation semiconductor material. However, its extremely high hardness, brittleness, and corrosion resistance cause the diamond difficult to process, especially for large-size chemical vapor deposition (CVD) single crystal diamonds (SCD). Currently, researchers have not explored an efficient and low-cost method for ultra-precision processing diamond wafers. Based on the rotary infeed surface grinding, integrated processing technology of grinding and polishing by the concentric double grinding wheel was proposed in this paper. In one clamping, the SCD surface is flattened by the inner ring ceramic grinding wheel that the abrasive is diamond, and then the surface after grinding is polished by sol-gel (SG) polishing wheel that the abrasives are diamond mixed with CuO. In the processing of grinding and polishing integration, the surface roughness of SCD can be reduced from about 46 nm to less than 0.3 nm in a short time. In the grinding, the ceramic grinding wheel with diamond abrasive scratches the SCD surface at high speed. The strong mechanical action causes the large material removal, obtains nano-level smooth surface of SCD, and causes the surface amorphization. In the SG polishing, the diamond abrasive scratches the SCD surface at high speed to form a high-temperature and high-pressure environment, which further induces the oxidation-reduction reaction between the CuO powder and the amorphous carbon for realizing reactive polishing. The integrated processing technology of grinding and polishing provides a reference for the industrial production of SCD wafers and polycrystalline diamond (PCD) wafers in the future.