Abstract: EMA,CEA, Ber-Ep4, KL-1, PKK-1 tests were carried in 27 cases of colonic medium defferentiated adenocarcinoma for immunohistochemical analysis to investigate antigenic expressions and their clinical significance. We chose 27 samples of medium differentiated adenocarcinoma in different position. In which there were 7 cases of ileocecal carcinoma, 5 cases of ascending colon, 5 cases of descending colon, 5 cases of sigmoidal colon, 5 cases of rectum, 10% formalin fixation and paradffin imbedding were used for all specimen. We adopted BSA method. The mouse monoclonal antibody was used by first, namely:antihuman carcinoembryonic antigen (CEA) antibody CMOIO (MOQIDA Pharmacy Tokyo), antihuman epithelial membrane antigen (EMA) antibody E29, antihuman epithelial property antigen-antibody Ber-Ep4, antihuman low molecular cellular keratin antibody PKK-1 (40, 45, 52.5KD) and KL-1 (56KD). Result: EMA showed strong positive reaction in 22.2%, BerEp4 in 55.5%, CEA in 59.2%, PKK-1 in 62.9%, and KL-1 in 100%. Result also indicated that all antigen expression except KL-1 were stronger in the part distal to descending colon. For colonic medium differentiated adenocarcinoma not only KL-1, CEA were good label, but also PKK-1, BerEp4 were of great importance in carcinoma of ileocecum, sigmoid and rectum.