Normal fasting blood glucose is 3.9 to 6.1 mmol/L, two-hour postprandial blood glucose is normally less than 7.8 mmol/L, and random blood glucose should be less than 11.1 mmol/L. Fasting blood glucose is required to be measured during overnight fasting, and the normal range is 3.9-6.1mmol/L; two-hour postprandial blood glucose is required to be calculated after two hours from the first bite of food, and the normal range should be less than 7.8mmol/L; random blood glucose should be less than 11.1mmol/L under normal circumstances. If the fasting blood glucose is more than 7mmol/L, the two-hour postprandial blood glucose is more than 11.1mmol/L, and the random blood glucose is more than 11.1mmol/L, it is necessary to consider the existence of diabetes mellitus, and it is recommended to combine with the typical clinical symptoms under the guidance of the doctor or repeat measurements to make a definite diagnosis. It is recommended to go to the hospital and ask the doctor to make a judgment if the blood glucose value is abnormal.