The normal range of fasting blood sugar is 3.9-6.1mmol/L. 9.0mmol/L indicates elevated blood sugar, which is a more serious condition. If the patient has no history of diabetes, he or she should promptly visit the hospital for further investigation of glucose tolerance test and glycated hemoglobin, etc. to clarify whether he or she has diabetes. If diabetes is diagnosed, typing should be performed and regular treatment should be given by an endocrinologist. If the patient has a history of diabetes and fasting glucose of 9.0 mmol/L indicates poor glycemic control, the glucose-lowering treatment plan should be adjusted promptly. In addition to medication as prescribed by the doctor, diabetic patients should also pay attention to diet regulation in general, eating less and more meals, low sugar, low salt and low fat diet. Increase exercise appropriately, such as brisk walking, jogging, swimming and other aerobic exercises. Actively monitor blood sugar and use hypoglycemic drugs as prescribed by the doctor to keep blood sugar within a reasonable range.