Abstract: Objective :To observe the pattern of change of the proliferation and the apopto-sis in the different stages of the large intestine carcinoma in mice and explore the effects of the out of balance of the apoptosis and the proliferation on the different stages of the large intestine carcinogenesis. Methods : Using the experimental animal model of the large intestine carcinoma of the mice of KUNMING species induced by the subcuteneous injection of dimethylhydrazine (DMH), we observed the distribution and the density change of the proliferative and the apoptotic cells dynamically in a multistage way. The animals were killed in batches in the 12th, 18th, 24th, and 32th weeks of carcinoma induction seperately. And the apoptotic and the proliferative cells were labeled seperately using TUNEL and PCNA immunohistochemical staining methods. Results : In the normal mucosas of the mice, all the apoptotic cells were situated in the superficial layers, however, the proliferative cells were situated in the basement layers, and the amounts of both of them were rare, In the early stage of the carcinoma induction, the proliferative and the apoptotic cells slightly increased in amount,but there were no obvious changes in the ratio of them. In themedium stage, the densities of both of them increased distinctly, but there were no obvious changes in the ratio. In the late stage,the densities of the proliferative and the apoptotic cells in the non-carcinoma mucosas were higher than those in other phases. The proliferative cells in-creased in the atypical hyperplastic mucosas and increased progressively with the degree of the lesions.Although the apoptotic cells increased,their changes were not with the degree of the le-sions.And the ratio of them showed a decreased tendency with the degree of the lesions. Conclu-sions : 1) The presence of the out of balance of the cell proliferation and the apoptosis was con-firmed in the course of the large intestine carcinogenesis in a mice model. 2) In the early Stage of the carcinoma induction the proliferation and apoptosis are both in a low degree; in the medi-um stage, they are both in a high degree; and in the late stage (that is in carcioma), the prolifer-ation is in a very high degree,but the apoptosis is in a low degree. 3) The proliferative cells in-creased progressively with the degree of the atypical hyperplasia.There were no obvious changes in the apoptotic cells. And the ratio of them showed a progressively increased tendency. 4) In the canceration stage,the most essencial change was the excessive decrease of the ratio of the apopto-sis and the proliferation. These results support the hypothesis of “he selected proliferation of the cells”, which was raised by us previously in a study on human large bowel carcinoma.