A fasting blood sugar of 20+ mmol/L generally requires consideration of hospitalization. The normal range of fasting blood glucose is generally 3.9~6.1mmol/L. The occurrence of fasting blood glucose more than 20mmol/L indicates that the blood glucose has far exceeded the normal range, and even diabetic ketoacidosis may occur, and if the long-term blood glucose control is not good, it will also induce diabetic nephropathy, retinopathy and other serious complications, so it is recommended to be hospitalized. Such patients need to be treated with insulin injections under the guidance of a doctor, with dietary control and other methods to stabilize blood glucose control before being discharged from the hospital; if diabetic ketoacidosis occurs, you also need to carry out insulin infusion, rehydration therapy, and so on. Patients with fasting blood glucose of more than 20 mmol/L are recommended to go to the hospital as soon as possible, and ask the doctor to make a judgment and give a treatment plan.