Abstract: A systematic study on the low damage processing of titanium gemstone crystal surface was carried out. The orthogonal experiment was carried out on the CCOS numerical control small grinding head polishing machine. Different polishing liquids were used to chemically polish the titanium gemstone to effectively remove the subsurface damage during the fine grinding stage. The experiment proves that the SiO2 silicon solution has good polishing effect as an abrasive, and is suitable as a polishing liquid for processing titanium gemstone. The four factors of polishing disc type, polishing disc pressure, polishing disc speed and silica sol dilution concentration and the relationship between surface roughness and surface rickets of titanium gemstone crystal were studied, and the influence of process parameters on the process of low-defect processing of titanium gemstone was obtained. Experiments were carried out according to the optimized process parameters, and a low-defect, high-precision titanium gemstone surface was obtained. The method of grayscale correlation was employed to optimize polishing parameters. After optimization, the system was under the condition of the best combination of processing technique. Finally, a well processed titanium gemstone crystal is obtained, the surface of which possesses a roughness of 0.262 nm and the surface defect rate of the polished crystal is 1.410-3 mm-1.