The 2-hour postprandial blood glucose 20mmol/L is significantly elevated for both normal people and diabetics, and may be more serious. 1. The normal value of 2-hour postprandial blood glucose for normal people is below 7.8mmol/L, so a significant increase in 2-hour postprandial blood glucose of 20mmol/L may be caused by diabetes, infection, stress and other disease factors, and it is recommended to consult a doctor as soon as possible to clarify the diagnosis and treatment. 2. For patients who have been diagnosed with diabetes in the past, the general 2-hour postprandial blood glucose needs to be controlled at 10mmol/L or less, so the 2-hour postprandial blood glucose of 20mmol/L is far more than the control target, which may induce diabetic ketoacidosis or diabetic hyperosmolar hyperglycemia syndrome and other acute complications of diabetes, and so it may be more serious. When a patient has a 2-hour postprandial blood glucose of 20mmol/L, it is recommended that he or she seeks medical attention in a timely manner under the guidance of a physician.