In view of the increasing demand of high performance HgCdTe detector for the good quality CdZnTe substrate,the annealing modification of CdZnTe substrate is studied by high temperature vacuum annealing technology. The results show that the infrared transmittance of CdZnTe substrate is significantly improved,reaching over ≥60% in the infrared band at 2.5μm～25μm.The second phase inclusion in the wafer are greatly improved and no second phase inclusion (＞1μm) can be realized which means that the inclusions are not visible under infrared microscopy. The uniformity of the Zn component distribution is greatly improved,and by adjusting annealing partial pressure,the Zn components in the substrate can be adjusted and the component uniformity of the Zn value can be achieved,where the Zn component can be controlled in the range of 0.044～0.051 and the standard deviation of the composition can be controlled below 0.001. The component adjustable and uniformity of the substrate lays the substrate material foundation for improving the quality of large area array HgCdTe detector.