Fasting blood glucose 7.0mmol/L, if accompanied by symptoms of polyphagia, polydipsia, polyuria, unexplained weight loss, can be diagnosed as diabetes mellitus; if there are no symptoms, non-same day retesting of fasting blood glucose ≥ 7.0mmol/L, can be diagnosed as diabetes mellitus. Fasting blood glucose 7.0mmol/L has reached the diagnostic standard of diabetes mellitus, but it must be accompanied by the typical symptoms of diabetes mellitus such as polyphagia, polydipsia, polyuria, and unexplained weight loss to diagnose diabetes mellitus by the result of this test; if there are no symptoms, emotional excitement, stress reaction, etc., can lead to transient elevation of blood glucose, and the result cannot be confirmed. If fasting blood glucose is elevated without clinical symptoms, it is necessary to review the test on another day, and the results of both tests are ≥7.0 mmol/L, then diabetes can be diagnosed. When the diagnosis of diabetes mellitus is clear, it should be actively treated under the guidance of a doctor, and attention should be paid to controlling the intake of sugar and fat in daily life.