Oxidative stress is a major contributor to the pathogenesis of diabetes and diabetic complications. Heme oxygenase （HO）, an important part of the human defense system, has been recognized to have significant physiological function against oxidative stress. HO can be stimulated by oxidative stress and decompose into carbon monoxide, biliverdin and iron,all with important anti-inflammatory, anti-oxidative stress and anti-apoptosis effects. Overexpression of HO induced by hyperglycemia can protect cells （including islet cells, endothelial cells and monocytes） and tissues from oxidative damage. Increased HO metabolic products not only maintain the physiological function of islet cells, delay diabetes progression, but also regulate vascular, nerve and muscle function,so as to prevent diabetic complications.