Abstract: Surface damage caused by cutting on Si, InSb, HgCdTe has been studied by Reflection High Energy Electron Diffraction (RHEED) after step-etching the samples. The results have shown that under same cutting condition, the depth of damage layers is correlated with material itself being cut; The structure of damage layers varies with the depth of damage layers; Under different cutting conditions, the damage on the surface of a material is different. We consider that damage layers on near perfect crystal consist of polycrystal layer, mosaic structure layer and distorted layer.