High cystatin inhibitor C is known as high cystatin C. The cause of the disease should be clarified and treated according to the cause. The common causes of high cystatin C include diabetic nephropathy, hypertensive nephropathy or other causes of renal insufficiency, which can be treated by dietary adjustments and medications. Adults’ serum cystatin C ranges from 0.6 to 2.5 mg/L. The primary urinary cystatin C level is between 0.6 and 2.5 mg/L. The original urinary cystatin C in the proximal tubule is almost completely taken up and decomposed by the epithelial cells, and does not return to the blood, and only a trace amount of it is excreted in the urine, therefore, the serum cystatin C level is a sensitive and specific indicator to reflect the glomerular filtration function. If patients with diabetic nephropathy, low-salt and low-fat diet, moderate exercise, oral metformin, acarbose and other hypoglycemic drugs, or the application of insulin hypoglycemic therapy. For hypertensive nephropathy, ACEI or ARB drugs such as captopril and irbesartan can be applied to lower blood pressure. After active treatment of the primary disease, the condition is relieved and cystatin C may decrease. There may be other reasons for high cystatin C. It is recommended that patients go to regular hospitals in time, improve the examination to clarify the cause of the disease, and then give targeted treatment or therapy under the guidance of the doctor.