Objective:To investigate the correlation between DNA methltransferase 3a(DNMT3a) and histone deacetylase 2(HDAC2) expression and clinical parameters of gastric cancer. Methods:The expressions of DNMT3a and HDAC2 in 30 gastric adenocarcinoma tissues and paracancerous tissues were detected by Western blot. The expressions of DNMT3a and HDAC2 in 90 gastric adenocarcinoma tissues were detected by immunohistochemistry. The relationship between DNMT3a and HDAC2 expressions and clinicopathological features of gastric adenocarcinoma was analyzed. Results:The protein levels of DNMT3a and HDAC2 were significantly higher than those in paracancerous tissues(P < 0.01). The immunohistochemistry examination showed that the positive rates of DNMT3a and HDAC2 protein were 79%(71/90) and 86%(77/90) respectively in 90 gastric adenocarcinoma tissues,DNMT3a expression was positively correlated with the differentiation and lymph node metastasis(P < 0.05),HDAC2 expression was positively correlated with the pathologic classification,invasion degree,TNM stage and lymph node metastasis(P < 0.05). There was positive correlation between DNMT3a and DNMT3b(P < 0.05). Conclusion:DNMT3a and HDAC2 were risk factors in the development of gastric cancer and might reflect malignant degree and prognosis to a certain degree. For these reasons,they are useful markers of the tumor.