The patient’s fasting blood glucose measured by venous blood was 9.5 mmol/L, which met the diagnostic criteria for diabetes. Because the diagnostic standard of diabetes is fasting blood glucose >7mmol/L or more, the patient was advised to recheck fasting blood glucose again in the same hospital after 2-3 days. And the patient is instructed to finish dinner at 7:00 on the day before the examination and not to eat any other food afterwards. If the blood sugar of still venous blood is around 9.5mmol/L, the diagnosis of diabetes is clear, and then the 2-hour postprandial blood sugar and glycated hemoglobin should be further checked to guide the treatment. Patients should pay special attention to diet control, first of all, foods with high sugar content should not be eaten, like snacks, cookies, drinks, fruits and thin rice. The amount of staple foods should be controlled, like rice, steamed buns, buns and dumplings strictly, and not too much should be eaten. Secondly, appropriate activities should be performed after meals. Finally, patients with fasting blood glucose up to 9.5mmol/L should be treated with oral hypoglycemic drugs, and metformin is generally preferred as the starting drug for treatment. If the blood sugar is not well controlled, other glucose-lowering drugs can also be combined. If necessary, testing insulin secretion is more helpful to guide treatment.