Recent studies have shown that diffuse large B-cell lymphoma (DLBCL) can be classified into germinal center B-cell-like (GCB) and non-GCB phenotypes by immunohistochemical staining. The aim of this study was to investigate the correlation of immunophenotypic classification with clinicopathological features in Chinese patients with primary gastric DLBCL to further our knowledge of this disease. Seventy-three patients with a histopathological diagnosis of primary gastric DLBCL were studied. Immunohistochemistry was carried out using the EnVision method to detect the expression of CD10, Bcl-6, and MUM1. The clinicopathologic features and follow-up data were analyzed using the Kaplan-Meier method, log-rank test, and χ (2) test. Expression of CD10 was observed in 21.9 % (16/73) of patients, Bcl-6 in 72.6 % (53/73), and MUM1 in 74.0 % (54/73). According to these data, 32.9 % (24/73) of the cases belonged to GCB subtype and 67.1 % (49/73) belonged to non-GCB subtype. There was a significant difference in tumor size and local lymph node metastasis between the GCB and non-GCB groups (P < 0.05). Complications in the GCB group (4.2 %) occurred less frequently than those in the non-GCB group (18.4 %); however, this difference was not significant (P > 0.05). Survival analysis revealed that patients in the GCB group had an increased 5-year survival rate compared to those in the non-GCB group (58.5 % vs 35.7 %, χ (2) = 3.939, P < 0.05). The 5-year survival rate of patients undergoing R-CHOP chemotherapy was significantly longer than that of patients in the CHOP group (74.7 % vs 37.5 %, χ (2) = 4.185, P < 0.05). The immunophenotype classification of primary gastric DLBCL, which is closely related to the tumor size and local lymph nodes metastasis, was found to have prognostic significance.