Objective To investigate the baseline immunity function status in the eldly type 2 diabetic patients by analyzing the change in peripheral blood lymphocyte subsets.Methods Lymphocyte subsets in the peripheral blood were detected by flow cytometry in 60 eldly patients with type 2 diabetes and 56 old control.Results The diabetic group had a lower percentages of CD3+ ,CD19+，CD4+ lymphocytes,NK cell,and lower CD4+/CD8+ ratio than the control group (p<0.05)，and had a higher percentage of CD8+ cell than the control group(p<0.05).Conclusion The T lymphocyte immunological functions in the eldly patients with type 2 diabetes were generally inhibited. Detection of the variations of lymphocyte subsets in peripheral blood may be used in the monitoring of immune function for the eldly patients with type 2 diabete.