The condition of high blood glucose but not meeting the criteria for diagnosing diabetes is medically known as abnormal glucose tolerance (IGT), which refers to an intermediate state between diabetes and normal people in which blood glucose exceeds normal levels but does not meet the diagnostic criteria for diabetes after taking 75g of glucose orally. 1999 WHO diagnostic criteria for abnormal glucose tolerance are fasting blood glucose 6.1-7.0mmol/ L, and blood sugar 7.8-11.1mmol/L 2 hours after taking 75g glucose solution orally. These patients cannot be diagnosed as diabetic yet, but their risk of developing diabetes later, leading to atherosclerosis and mortality are higher than the general population. At this time, if lifestyle changes, diet control, appropriate physical exercise or taking anti-diabetic drugs are effective, the progression to diabetes can be prevented or delayed. Therefore, abnormal glucose tolerance is a prelude to diabetes, also known as “pre-diabetes”. Abnormal glucose tolerance is a reversible stage, a compensatory stage of the disorder of glucose metabolism in the human body, and a transitional stage from abnormal glucose tolerance, i.e., early diabetes, to diabetes. Abnormal glucose tolerance does not mean that the patient has diabetes, but it means that the patient’s pancreatic islet function has become abnormal and he is more likely to develop diabetes than normal people, while increasing the risk of cardiovascular disease and microvascular disease. Therefore, interventional treatment of abnormal glucose tolerance is the key to preventing type 2 diabetes.