Objective To observe the protective effects of short-term continuous subcutaneous insulin infusion (CSⅡ) therapy on the peripheral blood circulating endothelial progenitor cells (EPCs) in patients with newly diagnosed type 2 diabetes mellitus (T2DM) and its antioxidation mechanism. Methods Forty T2DM patients (T2DM group) and 30 controls (control group) were involved in this study. Density gradient centrifugation was used to collect peripheral blood mononuelear cells. After 7 days' inducement and differentiation, FITC-UEA and DIL-acLDL double staining cells were identified to be differentiated EPCs by laser scanning conform microscope, and they were counted under inverted microscope. Serum levels of reactive oxygen species (ROS), malondialde-hyde (MDA), glutathione (GSH), superoxide dismutase (SOD) were examined. Results In T2DM group, the EPCs in peripheral blood were significantly reduced (46 ± 3 vs 23 ± 4, P< 0.01), BOS and MDA increased[(1125 ± 687) U/ml vs(2088 ± 765) U/ml, (4.58 ±3.03) μ mol/L vs (8.32 ± 4.15) μ mol/L, P < 0.01] , and GSH and SOD decreased [(263 ± 35) mg/L vs (206 ± 41) mg/L, (103 ± 7) U/ml vs (80 ± 15) U/ml, P < 0.05] . EPCs were negatively correlated with BOS and MDA (r = -0.7352,P < 0.01 ;r = -0.8454, P < 0.01) and was positively correlated with GSH and SOD (r =0.5435,P <0.05;r =0.6437,P <0.05). After short-term CSⅡ therapy, EPCs, GSH, and SOD in patients with T2DM significantly increased (P < 0.05),but BOS and MDA significantly decreased (P <0.05). Conclusion Short-term CSⅡ therapy can significantly reduce oxidative stress in patients with T2DM, promote the restoration of EPCs, and then prevent vascular disease.