Diabetic nephropathy can occur in about 20%-40% of patients with diabetes mellitus; the incidence of nephropathy in type 1 diabetic patients is related to the duration of diabetes mellitus, with an incidence of 40-50% in those with 20-25 years of disease; the incidence of diabetic nephropathy in type 2 diabetic patients is about 20%-50%. In the early stage of diabetic nephropathy, the urinary routine protein is mostly negative, while the urinary albumin excretion continues to exceed normal (up to 20-200 g/min or 30-300 mg/24h); in the clinical proteinuria stage, the urinary routine protein continues to be positive, and the urinary protein quantification is >0.5 g/24h; if it enters the middle and late stage of renal failure, the symptoms of uremia can gradually appear. Therefore, patients with diabetes mellitus should have their urinary routine and urinary albumin excretion rate checked regularly, especially those with a history of diabetes mellitus for more than 5 years, and should be tested at least 2 or more times a year.