Normal fasting blood glucose refers to the blood glucose of fasting venous blood measured after 8 hours of fasting and water, which is 3.9-6.1mmol/L. If diabetic patients are under strict control, in principle, no matter whether it is through the use of medication or insulin glucose-lowering treatment, the range of blood glucose control is the same as that of normal people. That is, the fasting blood sugar of diabetic patients should also reach 3.9-6.1mmol / L. However, for the elderly or patients with a longer duration of diabetes, you can appropriately widen the value, there is no need to control blood glucose so tightly, resulting in the quality of life of the elderly, especially the elderly patients decline, you can control the fasting glucose at 7mmol / L or 8mmol / L or so.