A dense and homogeneous nanograins diamond like carbon(DLC)film was deposited on the well polished HgCdTe wafer by radio frequency plasma chemical vapor deposition at room temperature. The interface of DLC?HgCdTe was studied by AES and compared with that of ZnS?HgCdTe, which was prepared by ion sputtering(IS).The result shows that both DLC film and ZnS film can suppress the dissociation of the weak bonding HgTe, and prevent Hg escaping from MCT surface to some extent. However, both Zn and S in ZnS layer tend to diffuse inward MCT, while diffusion of C from DLC layer into MCT is rather slight. In particular, IR transmission of MCT deposited with DLC is remarkable raised comparing to the naked surface and higher than that of MCT deposited with ZnS.