After diabetic nephropathy occurs in diabetic patients, the rate of progression to end-stage nephropathy is 14 times faster than other kidney diseases, so it is important to prevent and delay the occurrence and development of diabetic nephropathy. The prevention and treatment of diabetic nephropathy can be divided into 3 stages. Stage 1 is the prevention of diabetic nephropathy, carrying out screening for diabetes and timely intervention to prevent the occurrence of diabetes and diabetic nephropathy. Phase 2 is the early treatment of diabetic nephropathy, active treatment at the stage of microalbuminuria can make some patients’ condition reversed. Stage 3 is to prevent the occurrence and delay the progression of renal insufficiency in patients with diabetic nephropathy. The treatment of diabetic nephropathy includes the following aspects: 1. Diet therapy Diet therapy is one of the basic treatments for diabetic nephropathy. Controlling body weight within the normal range and obtaining ideal blood glucose, blood lipids and blood pressure with drug therapy are important for further protection of renal function. 55%~65% of total dietary calories are provided by carbohydrates, and patients should be encouraged to consume more complex carbohydrates and carbohydrates rich in soluble food fiber and fiber-rich vegetables. The control of total carbohydrate calories is more important than the control of food types. 20-30% of the total dietary calories should come from fats and oils. If the patient’s LDL level is 2.6 mmol/L, the intake of saturated fatty acids should be less than 10% of the total calories, and the cholesterol content of food should be less than 300 mg/d. Protein should not be more than 15% of the total calories. In patients with microalbuminuria, protein intake should be controlled within 0.8~1.0g/kg body weight. For patients with proteinuria and renal impairment, the protein intake should be less than 0.6g/kg body weight. 2.Control high blood sugar Strict control of blood sugar can reduce the occurrence of diabetic nephropathy and delay the progress of its course, which is the basis of diabetic nephropathy treatment. Diabetic patients, especially in the early stage of type 2 diabetes, can control blood sugar by controlling diet and increasing physical activity, and eventually often need oral hypoglycemic drugs and insulin therapy. Patients with renal insufficiency are at increased risk of hypoglycemia, mainly because: clearance of insulin and some oral hypoglycemic drugs is decreased in renal insufficiency; renal parenchymal damage reduces the ability of renal glycogen isogenesis. Therefore, the incidence of hypoglycemia can be increased 5-fold with insulin therapy in patients with serum creatinine >194 μmol/L. The decreased clearance of sulfonylureas and their metabolites requires a reduction in the dose of the drug. In particular, the parent drugs of the 1st generation sulfonylureas and their metabolic components have renal metabolism, and patients with chronic renal insufficiency have a prolonged half-life of this class of drugs and an increased risk of hypoglycemia. Among the 2nd generation sulfonylureas hypoglycemic agents, glipizide and gliclazide can be preferred because these two drugs have no active metabolites and do not increase the risk of hypoglycemia in patients with renal insufficiency. Since metformin is mainly cleared by the kidneys, it tends to accumulate in doses in men with serum creatinine >132 μmol/L and in women with serum creatinine >124 μmol/L, making patients more likely to have lactic acidosis. 3, control hypertension Strict control of hypertension can significantly reduce urinary protein levels in patients with diabetic nephropathy, delay the progression of renal impairment, and reduce the occurrence of cardiovascular disease endpoint events. Generally speaking, the ideal blood pressure level for diabetic patients is 130/80mmHg, and when the quantitative urine protein is greater than 1g/24 hours, the blood pressure should be controlled below 125/75mmHg. Evidence-based medicine has confirmed the role of ACEI and ARB in controlling hypertension, reducing proteinuria and delaying the progression of renal function in patients with diabetic nephropathy, and they are the drugs of choice for controlling hypertension in diabetic nephropathy. In the process of medication, patients should be observed for changes in renal function, blood potassium and blood volume, and patients with renal artery stenosis should be used with caution or prohibited. Diuretics are also the basic drugs for controlling hypertension in diabetes. However, diuretics have the effect of lowering blood sodium, blood chloride and blood potassium, and raising blood glucose, blood lipids and uric acid, so attention should be paid to the effect of related complications. Thiazide diuretics can be effectively used in combination with ACEI, ARB and β-blockers, but the effect is poor when combined with CCB class. 4.correcting disorders of lipid metabolism Hyperlipidemia is prevalent in patients with diabetic nephropathy, and the role of lipotoxicity in the occurrence and development of diabetic complications is receiving increasing attention. Hyperlipidemia is not only directly involved in the occurrence of diabetic insulin resistance and cardiovascular complications, but low-density lipoprotein cholesterol (LDL) can also act on LDL receptors on glomerular thylakoid cells, leading to damage of thylakoid cells and podocytes, aggravating the progression of proteinuria and interstitial fibrosis of glomeruli and tubules. Therefore, actively correcting the disorder of lipid metabolism in diabetic nephropathy patients is of great significance in the prevention and treatment of diabetic nephropathy, which can improve proteinuria and delay the progression of renal function injury. Patients with diabetic nephropathy with LDL〉3.38mmol/L and triglycerides (TG)〉2.26mmol/L should start lipid-lowering therapy. The treatment goals are: LDL <2.26mmol/L or less, TG <1.7mmol/L. 5. Reduce proteinuria and protect renal function Proteinuria is an independent risk factor of diabetic nephropathy and is closely related to the progression of renal insufficiency, reducing proteinuria is one of the key aspects of the treatment of diabetic nephropathy. It is currently believed that the "triple high" phenomenon of proteinuria in diabetic nephropathy is related to the activation of the local renin-angiotensin-aldosterone system in the kidney. Local angiotensin II (Ang II) can increase the expression of TGF-β1 and fibrinogen activator inhibitor, and increase the production of extracellular matrix; through the activation of lymphocytes, it mediates the local inflammatory response in the kidney and accelerates the process of kidney tissue damage and fibrosis. Based on the above reasons, ACEI/ARB has the effect of reducing proteinuria, alleviating renal tissue lesions and delaying the progression of renal insufficiency in patients with diabetic nephropathy, in addition to its hypotensive effect.