Diabetic nephropathy can be divided into five stages according to clinical manifestations: Stage I: also known as glomerular hyperfiltration stage. It is characterized by increased renal volume, increased renal blood flow and glomerular filtration rate and creatinine clearance, but biochemical and trace protein are mostly negative. Stage II: Also known as the resting phase. It is characterized by the beginning of glomerular structural damage on renal biopsy, renal hyperemia and hyperfiltration still exist, and trace proteins are mostly normal, but they can also appear in the urine after exercise. Stage III: Also known as the occult stage. It is characterized by persistent microproteinuria, normal blood pressure at the beginning, and elevated GFR. In the later stages, blood pressure gradually increases and GFR decreases. Stage IV: Also known as the clinically dominant DN stage. It is characterized by: (1) Proteinuria. It is mostly intermittent at the beginning, and then gradually becomes persistent. When the total amount of urine protein exceeds 30g/24h, it indicates further aggravation of glomerular lesions. (2) Hypertension. About 75% of patients develop hypertension, and the degree of increase in blood pressure is positively correlated with the 24-hour protein excretion and the rate of DN development. (3) Progressive decrease in GFR, which is characterized by a progressive decrease in GFR without a decrease in protein excretion rate. (4) Edema. It starts from the eyelids and spreads to the whole body. In severe cases, multiple plasma cavities may develop. Stage V: Also known as renal failure. It is the end stage of DN, characterized by the decline of GFR to less than 1/3 of normal, azotemia, proteinuria, hypertension further aggravated, anemia, renal osteodystrophy, metabolic acidosis, hyperkalemia, uremic brain dysfunction, and finally death from uremic coma, secondary infection, cardiac insufficiency or cardiovascular accident.