HBV infection occurs mainly in hepatocytes, and the immune response triggered by T lymphocytes (immune cells of the body) plays an important role in the clearance and destruction of the virus in HBV-infected patients. During acute hepatitis B infection, the body can successfully clear the virus because the body’s T-cell immune cells are active and strong. In chronic hepatitis B infection, however, the body’s cellular immune response is weak and homogeneous, so it is not sufficient to clear the virus, and the viral infection continues to cause liver damage. As the disease progresses in chronic hepatitis B patients, the T-lymphocyte subpopulation is not only related to the course of the disease in hepatitis B patients, but also to the clinical stage of the organism. The body’s T-cell immune response is enhanced after antiviral therapy. Animal studies have found that the number of hepatic and peripheral HBV-DNA begins to decline before hepatic T-cell infiltration reaches its peak, and that antivirals inhibit viral replication while increasing the number of immune cells and their function in the body to facilitate further viral clearance. The regression and outcome of hepatitis B infection depends on the balance between the amount of virus infected and the immune response of the human organism against the virus. A rapid and effective antiviral immune response is durable in limiting the spread of viral infection. Therefore, protecting one’s cellular immune status as much as possible can greatly prolong the survival of hepatitis B patients, improve the quality of life, and increase confidence in treating the disease.