CdZnTe is the best substrate material for liquid phase epitaxial HgCdTe thin films.High quality CdZnTe substrate surface is very important to improve the performance of infrared detector.In this paper,the surface processing technology of CdZnTe was studied,and a new chemical polishing technology was developed,which making the surface roughness,Ra,of polished CdZnTe to 0.3 nm.