Over 65 years old, with life expectancy of more than 10 years and better self-management ability, and patients without combined serious heart, liver and kidney function damage, it is recommended that fasting blood glucose should be controlled below 6mmol/L and postprandial blood glucose should be controlled below 8mmol/L. Some patients with life expectancy between 5 and 10 years, combined with serious liver and kidney function damage, it is recommended that the blood glucose control range should be relaxed, and fasting blood glucose should be below 8mmol/L and two-hour postprandial blood glucose should be below 10mmol/L. For a small number of patients, even though their life expectancy is more than 10 years, their blood glucose fluctuates greatly, which is called brittle diabetes; or for some patients whose life expectancy is less than 5 years, such as cancer patients and patients with serious damage to the target organs of heart, brain and kidney, the blood glucose control range should be more relaxed, and random blood glucose between 8-12mmol/L is sufficient.