Inclusion Criteria:  type 2 diabetes patients are in line with the relevant diagnostic criteria in China's guideline for prevention and treatment of type 2 diabetes (2017 Edition). patients with diabetic nephropathy are in line with the relevant diagnostic criteria in the expert consensus on diabetic nephropathy (2014 Edition).  Exclusion Criteria:  Primary kidney disease (e.g. acute and chronic glomerulonephritis, immune and hereditary nephropathy, pyelonephritis, gout related nephropathy, etc.) Abnormal changes of microalbuminuria and urine glucose caused by other factors (such as urinary system infection, fever, 24-hour strenuous exercise, intractable hypertension, congestive heart failure, pregnancy, ketoacidosis, etc.) Failure of other important organs (heart, lung and liver) in the whole body; Activity of urinary sediment; The glomerular filtration rate decreased by more than 30% within 2-3 months after treatment with angiotensin converting enzyme inhibitor (ACEI) or angiotensin Ⅱ receptor antagonist (ARB); Patients with cancer, trauma, stress and other endocrine diseases; Patients with type 1 diabetes and kidney injury; Congenital mental retardation or poor compliance; The informed consent was not signed.