Objective: To investigate the level of IL-10 expressing on induced Treg cells（iTreg） such as CD4+CD25+T cells of SLE patients. Methods: Peripheral blood mononuclear cells(PBMCs) were isolated from healthy donors and SLE patients, respectively, and CD4+CD25-T cells were further isolated. Then the cells were induced and transformed by TGF-β in vitro; expression of intracellular and membrane IL-10 on CD25+ and CD25-,Foxp3+ and Foxp3- subsets of induced and transformed T cells were analyzed by flow cytometry. Results: Expression level of the intracellular IL-10(iIL-10) in CD25+ T cell subsets was obviously increased in both of the induced and transformed CD4+T cells from the normal controls and SLE patients, but it was significantly higher in the SLE patients. In the induced and transformed CD4+T cells both from the normal controls and SLE patients, expession level of the membrane IL-10 in CD25+ T cell subsets was obviously increased, while it had no difference between the SLE patients and the control group. In the normal subjects and SLE patients, the expession level of intracellular IL-10 in the induced and transformed CD4+CD25+ Foxp3+T cells subsets was obviously increased, and was significantly higher in the SLE patients than that of the control group. The expession level of membrane IL-10 was increased in the induced and transformed CD4+CD25+ Foxp3+T cells subsets, while no difference was observed between normal subjects and SLE patients. All the changes mentioned before have no correlation with SLEDAI. Conclusion: The IL-10 expression level was closely correlated with the induced and transformed CD4+CD25+ Foxp3+ Treg cells from the normal subjects. Abnormal expression of intracellular IL-10 was observed on the induced and transformed Treg cells from the CD4+CD25-T cell of SLE patients. The intracellular IL-10 exprssion level of CD4+CD25+Foxp3+ Treg cells from the SLE patients was significantly higher than that of the control group. And the intracellular IL-10 exprssion level of CD4+CD25+ Foxp3- Treg cells and CD4+CD25-T cell without induction was also significantly higher than that of the control group; But the expessions level of membrane IL-10 was not different between the SLE patients and the normal controls.