Cadmium zinc telluride (CdZnTe) crystal has excellent performance and is the preferred substrate material for high-performance HgCdTe epitaxial films. Double sided polishing is a kind of surface polishing method for CdZnTe wafers, which has the advantages of high efficiency, good flatness and less stress accumulation in wafers. However, when the size of CdZnTe wafer increases, the processing difficulty also rises, and the problems such as many debris, slow processing speed and poor surface flatness are prone to occur. In this paper, the double sided polishing technology of irregular CdZnTe wafer with an area of more than 50 cm2was studied. The effects of different parameters on the polishing quality were simulated and optimized. The particle size of the polishing liquid, polishing pressure, and flow rate of the polishing liquid were optimized by simulating and optimizing the path of wafer. The double sided polishing process with high polishing speed and better surface quality is realized for large size irregular CdZnTe wafers, which is of great significance for further research on the double sided polishing technology.