Abstract: Objective to investigate the relationship between the content of serum maleic dialdehyde （MDA）, superoxide disdmutase （SOD）and reduced glutathione （GSH） with complication of type 2 diabetic mellitus. the influence and mechanism of oxidaive stress on diabetic nephropathy，so as to ofter theoretic evidences for clinical therapy. Methods：50 cases of the control group of healthy patients；150 cases with type 2 diabetes mellitus is divided into three groups of patients with normal albuminuria group, microalbuminuria and clinical proteinuria group, each group contens 50 cases. ELISA assay with serum homocysteine, spectrophotometer serum MDA, SOD, GSH content. Results：All patients with diabetes serum homocysteine, MDA levels were significantly higher than the normal control group (P <0.01); micro-albuminuria albuminuria group and clinical group were higher than normal albuminuria group and normal control group (P <0.01); clinical albuminuria group was higher than the microalbuminuria group (P <0.01); Serum SOD, GSH content of all the diabetic patients were lower than normal control group (P <0.01); micro-albuminuria albuminuria group and clinical group lower than those without nephropathy (P <0.01); serum homocysteine level and the level of serum MDA was positively correlated with serum homocysteine levels and SOD, GSH content showed a negative correlation（ P <0.01）. Conclusion：Serum homocysteine damage through oxidative stress involved in the occurrence of diabetic nephropathy development process.

Key words: Type 2 diabetic mellitus, Diabetic nephropathy, Homocysteine, Oxidative Stress