Abstract: OBJECTIVE To investigate the changes of peripheral blood T lymphocyte subsets, interferon gamma (IFN-γ), tumor necrosis factor alpha (TNF-α) of patients with hepatitis B viral (HBV) infection so as to analyze the immune function's role in the disease development. METHODS From Jan. 2013 to Jan. 2013, 450 patients with HBV infection were selected as study objects, and another 100 healthy people in the same period were chosen as control group. Changes of peripheral blood T lymphocyte subsets, IFN-γ and TNF -α levels were detected in the two groups. SPSS 19.0 was explored for statistical analysis. RESULTS T lymphocyte subsets in peripheral blood of HBV infection group were lower than that of the control group while IFN-γ and TNF-α levels were higher than those of the control group. The differences were significant (P<0.05).CD₃^＋, CD₄^＋, CD₄^＋/CD₈^＋ levels of HBV-DNA positive patients were lower than those with negative HBV-DNA, while IFN-γ level was higher. The differences were significant (P<0.05).Patients with acute HBV infection were proved to have lower CD₈^＋ level and CD₄^＋/CD₈^＋ ratio than patients with chronic and latent HBV infection, while IFN-γ and TNF-α levels were higher. The differences were significant (P<0.05). The CD₃^＋, CD₄^＋, IFN-γ and TNF-α levels of ,HBc-IgM positive patients after pure liver enzyme reduction treatment for 6 months were lower than patients treated with IFN-α. The differences were significant (P<0.05). CONCLUSION Hepatitis B patients have obvious immune function disorder, characterized by abnormal changes of peripheral blood T lymphocyte subsets, IFN-γand TNF-α and have a certain impact on disease outcome.