Using plane-wave pseudopotential methods based on the density functional theory, we have studied the structural and the electronic properties of gold doped Hg1-xCdxTe （MCT）. The results indicate that the in situ gold impurity maintains stabile bonds with the host atoms. Moreover, the in situ gold impurity creates a shallow acceptor level behaving as an efficient p-type dopant. For all mole fractions under molecular beam epitaxy （MBE） cation-rich growth condition, for 0.75＜x≤1 under MBE Te-rich growth condition, and for 0.75≤x≤1 under liquid phase epitaxy cation rich growth condition, the self-compensating effect occurs and the gold impurity cannot behave as an efficient p-type dopant in MCT.