Objective To detect T-lymphocyte subgroup in patients with malignant lymphoma, and investigate the relationship between the number of the cells and the oncogenesis and development of malignant lymphoma. Methods The counts of T-lymphocyte subgroup in peripheral blood of 106 patients with lymphoma were detected by flow-cytometry, and analyzed in comparison with that of 106 normal people as control. Results The counts of CD+3 cell and the ratio of CD+4/CD+8 in patients with malignant lymphoma were significantly lower than that of control group (P＜0.05). The number of CD+3 were significantly lower and CD+8 were higher than that of control group in patients with NHL at early ( Ⅰ, Ⅱ ) stage (P＜0.05). The counts of CD+3 CD+4 cell and the rate of CD+4/CD+8 in patients with NHL at advanced (Ⅲ ,Ⅳ) stage were significantly ldwer than that of control group (P＜0.05). Conclusion The function of immune is decreased in patients with malignant lymphoma, and these changes had correlation with clinic stage. It is of active significance by detecting T-lymphocyte subgroup in peripheral blood in patients with malignant lymphoma to evaluate the function of immune and find out the relationship between the number of the immune cells and the oneogenesis and development of malignant lymphoma.