Diabetes mellitus is caused by various etiologies and pathogenesis, resulting in absolute or relative lack of insulin secretion in the body and disorders in the metabolism of three major nutrients: sugar, protein and lipids, and is mainly characterized by chronic hyperglycemia, causing multi-system lesions in the heart, kidney, eyes and nerves. The main types of diabetes are type 1 diabetes and type 2 diabetes, and most of the diabetes in children is type 1 immune-mediated, mainly due to β-cell destruction, resulting in absolute insulin deficiency. The early symptoms of diabetes in children are mainly the following: 1, there is a sudden weight loss, but a large increase in the amount of meals easy to hunger, which is the most typical symptom of diabetes, easy to hunger and eat a lot, although eating a lot but still thin, which may be related to the lack of glucose in the whole body tissues and organs and the brain center to receive the signal of hunger and thus a symptom. 2, appear more drinking, more urination: children drink more water than usual, frequent thirst, and more night urination, or bedwetting, these situations should also be noted. 3.Fatigue and weakness, depression, easy infection: If the child suddenly becomes “lazy”, does not like to go out, and is depressed every day, it may be a precursor of diabetes, and needs to be alert and careful. 4. When repeated abdominal pain and nausea and vomiting occur, this point is easily overlooked as acute gastroenteritis. If you have frequent attacks, you need to go to the hospital in time for early detection and early treatment.