The extrinsic p-type doped HgCdTe material has the high minority carrier lifetime and can effectively improve device performance of long wave infrared or very long wave infrared HgCdTe detector.In this paper,the theory of p-type HgCdTe by As atom doping is reviewed.Also a preparation study of As doping p-type HgCdTe is given,which will be the basis for research about p-on-n HgCdTe materials and devices.