Diabetes mellitus is a common disease that is a metabolic disorder characterized by increased blood glucose levels caused by multiple etiologies. Hyperglycemia is caused by a defect in insulin secretion or action, or both. In addition to chronic hyperglycemia, diabetic patients are often accompanied by hyperlipidemia and hypertension, which can lead to lesions of the heart, blood vessels, nerves, eyes and kidneys over time, making diabetes an important cause of disability and death in humans. The causes of diabetes can be categorized into two main groups: genetic factors and environmental factors. Clinically, it can be divided into four major categories, namely type 1 diabetes, type 2 diabetes, other special types of diabetes and gestational diabetes. About 95% of diabetic patients in China are type 2 diabetic. With the improvement of people’s living standard, the prevalence of diabetes is on a rapid rise. The prevalence of diabetes has reached 12-15% in economically developed cities in China. Diabetes can cause a series of metabolic disorders such as sugar, protein, fat, water and electrolyte, etc. It can be asymptomatic in the early stage, but as the disease progresses, a large amount of glucose is excreted from urine, and symptoms such as excessive drinking, polyuria, polyphagia, wasting and weakness will appear. If the disease is not well controlled, further development will cause various acute and chronic complications throughout the body, seriously threatening health. Diabetes is also a preventable and treatable disease, a healthy lifestyle can keep you away from diabetes, and it is not terrible to have diabetes, a reasonable diet, moderate exercise, scientific treatment, close monitoring, to control blood sugar, blood pressure, lipids, etc. in the normal range, will enable you to live and work as normal people. According to epidemiological surveys, at least half of the patients with diabetes have no symptoms and are diagnosed only after blood glucose testing. Therefore, people with high-risk factors should be checked early for early treatment.