Objective:In order to know the clinical significance of the CD8+CD25+ T cell in autoimmune disease,hypersensitivity disease and organ transplantation, the normal limits of this T cell subset was obtained by studying the number of CD8+CD25+ T cell and its productions of IFN-γ,IL-10 and TGF-β in the normal peripheral blood. Methods:Mononuclear cells were isolated from healthy donors. The percentages and absolute numbers of CD8+CD25+,CD8+CD25-,CD8-CD25+ and CD8-CD25- from CD3+ T cells were detected by flow cytometry. In addition,stimulating with/without ionomycin and PMA 5 hours later,the expressions of IFN-γ,IL-10 and TGF-β in the CD8+CD25+ T cells was measured. Results:The percentage of CD8+CD25+ subgroup in CD3+ T cells from normal human peripheral blood was 2.52%,the absolute number was 37.09×106/L. The percentage and absolute number decreased after stimulated with ionomycin and PMA 5 hours. The expression of TGF-β on the surface of CD8+CD25+ T cells up to 93.8%,stimulation seems not obviously affected its expression but IFN-γ+ T cells increased obviously,however,IL-10+ T cells didn’t obviously up-regulat. Conclusion:There were a few CD8+CD25+ T cells in CD3+ T cells from normal peripheral blood. They expressed highly TGF-β in the cell surface,and could have IFN-γ reaction but no proliferation after stimulation.