Chemical-mechanical polishing is one of the key surface treatment processes for CdZnTe crystal. The chemical-mechanical slurry is an important factor affecting the surface quality of CdZnTe wafers. At present, most of the polishing slurry for CdZnTe wafers in our country is imported from foreign countries. This has greatly hampered the development of CdZnTe crystals of our country. In this paper, the alkaline chemical-mechanical slurry is prepared by using silica solution and NaClO as the main raw materials. Then, the slurry is used to polish the surface of CdZnTe wafers. The characterization result shows that the polished surface has its roughness less than 2 nm and the slurry can be used to treat the surface of CdZnTe wafers with high quality