Objective: To find out the relationship of the expressions of proliferating cell nuclear antigen (proliferating cell nuclear antigen, PCNA), alkaline phosphotase (alkaline phosphotase, AKP) and acid phosphotase (acid phosphotase, ACP) with the development of mouse fore stomach cancerization. Methods: The animal models, including the various stages during the development of NIH mouse fore stomach carcinoma, were made by N-Nitrososarcosineethylester (N-Nitrososarcosineethylester, NSEE). The mice were sacrificed on the 14th, 28th, 42nd, 56th, 70th and 84th days respectively after mice were irrigated with NSEE. The fore stomach was taken out and dissected. The methods of histopathology, immunohistochemistry and isoenzyme electrophoresis were adopted to study the dynamic changes of cell shape and expression of PCNA, AKP and ACP. Results: On the 42nd and 56th days after NSEE treatment, the expression of PCNA increased gradually along with the cancerization. Comparing with the control, there were significant differences (P＜0.05). On the 70th and 84th days, the expression of PCNA increased further (compared with the control P＜0.01). The activity of AKP increased gradually along with the cancerization. On the 14th, 28th, 42nd and 56th days, there were significant differences (P＜0.05); on the 70th and 84th days, the activity of AKP increased further (P＜0.01). The activity of ACP also increased on the 14th, 28th, 42nd and 56th days, and there were significant differences on the 70th days (P＜0.05) and on the 84th days (P＜0.01) compared with the control. Conclusion: During the carcinogenesis of NIH mouse fore stomach, the expressions of PCNA, AKP and ACP increased gradually and were consisted with the changes of cell shapes.