Fasting blood sugar 6.48mmol / L, sweet mouth after meal is not necessarily diabetes, need to improve the postprandial 2 hours blood sugar test, and need to pay attention. The standard value of fasting blood glucose is 3.9~6.1mmol/L, fasting blood glucose 6.48mmol/L belongs to the situation of high blood glucose, does not reach the diagnostic standard of diabetes, belongs to the impaired fasting blood glucose. For sweetness in the mouth after meal, it is necessary to perfect the 2-hour postprandial blood glucose test to know the blood glucose situation in the 2-hour postprandial period. If the 2-hour postprandial blood glucose ≥ 11.1mmol / L, that is to meet the diagnostic criteria for diabetes, if accompanied by more drinking, more urination, more food, weight loss of the “three more and one less” symptoms, in order to diagnose diabetes. If fasting blood glucose is 6.48mmol/L and sweetness in the mouth after meals, it is recommended to go to the hospital for a detailed examination.