The methods to confirm the diagnosis of diabetic nephropathy are usually as follows: 1. There must be a definite history of diabetes; 2. Urinary protein excretion rate, within 3 months of continuous examination, the glomerular urinary protein excretion rate exceeds 20-200 μg/min; 3. If other pathological causes of increased glomerular filtration rate can be excluded, early stage diabetic nephropathy can be diagnosed; 4. Persistent proteinuria, urinary protein >0.5 g/ 24h, more than 2 times in a row, and can exclude other causes of increased urine protein, can be diagnosed as clinical stage diabetic nephropathy. Clinically, any diabetic patient with increased urinary protein excretion rate, abnormally elevated urinary protein quantification, or the presence of edema, hypertension, renal impairment, or with diabetic retinopathy should be considered as diabetic nephropathy. Attention should also be paid to exclude urinary tract infections, or multiple causes of secondary kidney disease, as well as heart failure, hypertension and other causes of increased urinary protein excretion rate and urine protein.