Abstract: Objective: To study the expression of p53、Bcl-2 and PCNA gene in the gastric carcinoma and the adjacent mucosa. Methods: the expression of p53、Bcl-2 and PCNA gene were detected by immunohistochemical staining （LSAB ） in all the cases: 92 gastric adenocarcinomas and 24 simple superficial gastritis. Results: Abnormal expression of p53、Bcl-2 and PCNA gene in gastric carcinoma were significantly higher than that of non-cancer adjacent mucosa, they were related to the type of the gastric cancer. Abnormal expression in intestinal type were significantly higher than that in diffuse type. No significant difference were found between the early and the advanced, the cardiac and the antral gastric carcinoma. There were a closely consistent with the abnormal expression of p53 and Bcl-2 gene, p53 and PCNA gene. Conclusion: Gene mutation of p53 and abnormal expression of Bcl-2 and PCNA gene are important factor in the gastric carcinoma, particularly in intestinal type. There may be some relations about the functions of p53、Bcl-2 and PCNA gene.