Proteinuria in diabetes mellitus may be mainly due to the patient’s long-term poor glycemic control, resulting in diabetic nephropathy, with different prognosis for different degrees of severity. The prognosis of diabetic nephropathy varies according to the severity. Mild cases can usually be cured under the guidance of doctors. Diabetic nephropathy is divided into five stages, stage I, the main damage is the glomerulus. stage II lesions further progressed, in addition to damage to the glomerulus, the glomerulus outside the blood vessels inside the basement membrane thickening, or interstitial damage also exists. stage III proteinuria increased significantly, there may be mild hypertension. stage IV large amount of proteinuria, can be as high as 1.5 times the amount of proteinuria. Stage IV is characterized by massive proteinuria, up to the level of nephrotic syndrome.Stage V is characterized by uremia, renal failure, and most of the renal units have been completely damaged. Treatment includes early intervention of various risk factors and renal replacement therapy for end-stage renal disease. Dietary treatment should limit protein intake in the early stage. Some patients can control blood glucose, blood pressure and blood lipids, and urine protein can turn negative. Therefore, for diabetic patients, once proteinuria occurs, must pay attention to the treatment under the guidance of the doctor.