Diamond plays a significant role in the fields of mechanics, optics, thermology and electronics (such as semiconductors) with its excellent properties. However, the surface quality of diamond affects its application in these areas. Therefore, obtaining high-quality surfaces through efficient polishing technology has always been a focus of diamond research. The main diamond polishing technologies include mechanical polishing, thermochemical polishing, laser polishing and chemical mechanical polishing, among which chemical mechanical polishing (CMP) has the advantages of low equipment operating costs, simple process, and minimal surface damage after polishing. Based on the analysis and comparison of the above polishing methods, this paper focuses on the field of CMP and makes a detailed comparison and analysis of its development history. Although the early CMP technology had certain limitations in process and polishing efficiency, it lays the foundation for the innovation and optimization of the subsequent technology; the application of H₂O₂ and its mixtures not only enhances the chemical reaction activity in the process of CMP and improves the material removal rate, but also effectively reduces the surface roughness and improves the surface quality of diamond; the photocatalytic assisted chemical mechanical polishing can enable diamond to achieve a high surface quality, but the equipment is relatively complicated and cannot meet the demand of mass production, which needs further research and optimization. In addition, this paper also predicts the future development of chemical mechanical polishing to provide reference for researchers in related fields.