Blood glucose as high as 20mmol/L is recommended to be immediately hospitalized in the endocrinology department for systematic treatment, because whether it is fasting blood glucose of 20mmol/L or random postprandial blood glucose of 20mmol/L, this blood glucose level is more dangerous for people, especially for patients whose pancreatic islet function is not particularly good, and there is a risk of acute complications of diabetes in a short period of time. It is required that when the blood glucose reaches 20 mmol/L, the patient must be hospitalized and receive intensive glucose-lowering treatment program to ensure the safety of the patient. Even for patients whose pancreatic islet function is still okay, once blood sugar rises above 20mmol/L, conditions related to high glucose are likely to occur, and this condition also requires hospitalization for systematic management. Patients with blood glucose of 20mmol/L are less effective at home with medication alone.