Postprandial blood glucose counts time from the first bite. Clinically, 2 hours postprandial blood glucose is mostly used as an assessment indicator. For glucose tolerance test, fasting blood glucose is measured before starting, followed by dissolving 75g of anhydrous glucose in 250-300ml of water, requiring 5 minutes to drink, and then measuring blood glucose after 0.5 hours, 1 hour, 2 hours and 3 hours respectively. When monitoring blood glucose at home, testing postprandial blood glucose should start counting time from the first mouthful of meal. Among the postprandial blood glucose, 2-hour postprandial blood glucose is often used clinically as an assessment indicator. The normal 2-hour postprandial blood glucose is less than 7.8mmol/L, 7.8~11.0mmol/L belongs to impaired glucose tolerance, ≥11.1mmol/L and at the same time there are “three more and one less” clinical manifestations, it can be diagnosed as diabetes mellitus. It is recommended to consult a doctor in case of abnormal blood glucose.