Patients with SARS-CoV-2 infection often exhibit significant changes in T cells, particularly a reduction in CD4 + T and CD8 + T cells in peripheral blood, which has become a key feature of severe respiratory infection. These immune changes in T lymphocytes are closely associated with disease progression, but the specific mechanisms remain unclear and warrant further investigation. This paper reviewed the changes in the number and function of T cells in respiratory viral infections, with a focus on SARS-CoV-2, and summarized related therapeutic explorations. We believe that improving and enhancing the number and function of T lymphocytes in infected hosts is a promising strategy for the treatment of respiratory viral infections, although more systematic and in-depth scientific research is still needed.