Two hours after a meal is generally timed from the first bite of food consumed. Two hours postprandial generally refers to the measurement of blood glucose two hours after a meal. Two-hour postprandial blood glucose reflects the change of blood glucose after eating, which can reflect the function of pancreatic islet cells in the body, as well as the ability to regulate blood glucose after the secretion of insulin, and can be combined with fasting blood glucose, glycated hemoglobin and other indexes to jointly assess the condition of diabetes mellitus. The common checking time is from the first bite of food, excluding drinking water. Blood is drawn two hours later to measure blood glucose. The timing of the test will have a certain effect on the blood glucose value, and it is recommended to standardize the operation under the guidance of the clinician.