Abstract: The aim of the present study was to investigate the effect of kinetin on T lymphocyte subsets in peripheral blood and immunity of aging mice. The Kunming mice were randomly assigned to young control group, aging model group, low dosage kinetin treatment group, moderate dosage kinetin treatment group, and high dosage kinetin treatment group. To prepare the aging model, mice were subcutaneously administered 125 mg/（kg·BW）of D-galactose in their back skin. The low, moderate and high dosage kinetin treatment groups were intraperitoneally administered 5, 10 and 20 mg/（kg·BW）of kinetin solution, respectively.The young control group received no treatment. The changes in T lymphocyte subsets in peripheral blood, the binding capability of red blood cell to C3 b R and ICR, and the apoptosis of lymphocyte in thymus and spleen of different groups were assessed. The results revealed that different levels of kinetin were able to increase the percentage of CD3＋, CD4＋, CD8＋T lymphocyte subsets in peripheral blood and RBC-C3 b R rosette rate, and reduce the RBC-ICR rosette rate and apoptosis rate of lymphocyte in thymus and spleen. The combined data showed that kinetin could enhance immunity and delay immune senescence of mice.