In this report, series of annealing experiments under different temperatures of Au-doped Hg Cd Te covered by Cd Te have been implemented. The annealing process can improve the crystal state of electron beam evaporated Cd Te layer. The interface betw een Cd Te and Hg Cd Te can also be modified. The Au doping distribution in Hg Cd Te did not change after the vacuum annealing at 240℃ and300℃. How ever, the Au element diffused into the Cd Te cap layer significantly, leading to a higher concentration of ( 5 ~ 6) × 1016 cm-3. On the other hand, the concentration of mercury vacancy after various annealing processes w as different due to the temperature-dependent diffusion mechanism. In general, the carrier concentration measured by HALL effect varied from 2 × 1016 cm-3 to 5. 5 × 1016 cm-3, when the annealing temperature was increased from 240℃ to 300℃.