The typical manifestations of elevated blood glucose in diabetes mellitus are mainly “three more and one less”, i.e., drinking more, urinating more, eating more, and weight loss, while some patients may have no obvious symptoms. “Three more and one less” is a typical clinical manifestation of diabetes, but it does not mean that all diabetic patients will have all or some of the symptoms of “three more and one less”. Atypical diabetes symptoms may also include numbness in the hands and feet, wounds that do not heal easily, and acute cardiovascular disease. For obesity, alcoholism, a family history of diabetes and other conditions of patients should pay attention to regular monitoring of fasting, two hours after meals and glycated hemoglobin index, in order to determine the existence of diabetes, early detection, early treatment, and can not be diagnosed only through clinical symptoms. It is recommended that patients with abnormal blood glucose or the above symptoms should consult the Endocrinology Department in a timely manner for a clear diagnosis and timely treatment.