Diabetes mellitus is a common and frequent clinical condition and a worldwide public health problem that poses a serious threat to human health. Diabetes is a group of metabolic diseases characterized by chronic hyperglycemia caused by multiple etiologies. It is caused by defective insulin secretion and/or action, a clinical syndrome caused by a complex etiology of genetic and environmental factors, and its etiology and pathogenesis are not fully understood. Long-term disorders of carbohydrate, fat and protein metabolism can cause multi-system damage, leading to chronic progressive lesions, hypofunction and failure of the eyes, kidneys, nerves, heart, blood vessels and other tissues and organs; acute severe metabolic disorders, such as diabetic ketoacidosis and hypertonic hyperglycemic syndrome, can occur in severe conditions or stress. Diabetes mellitus is divided into type 1 diabetes mellitus (T1DM), type 2 diabetes mellitus (T2DM), other specific types of diabetes mellitus (e.g., genetic defects in islet action, pancreatic exocrine diseases, uncommon immune-mediated diabetes mellitus, etc.), and gestational diabetes mellitus, of which T2DM is the most common, accounting for about 90%-95%. The basic clinical manifestation of diabetes mellitus is a metabolic disorder syndrome: the typical manifestation of “three more and one less”: drinking more, urinating more, eating more, and losing weight, which may be accompanied by itchy skin, blurred vision, and other complications.