Childhood obesity is a worldwide public health problem. In recent years, the number of obese children in China has been increasing. Simple obesity is caused by genetic and environmental factors, of which environment is the main factor. Among environmental factors, family lifestyle and personal behavior pattern are the most important risk factors. Childhood obesity affects the growth and development of adolescence. Its serious harm will involve the endocrine and metabolic system, respiratory system and bones, have adverse effects on psychology, behavior, cognition and intelligence, and increase the risk of obesity related chronic diseases in adulthood. Childhood obesity increases the risk of type 2 diabetes in children. Overweight school-age children are 2.4-7.1 times more likely to have elevated cholesterol, low-density lipoprotein and triglycerides than their peers. Almost half of obese children have dyslipidemia, which is common in hypertriglyceridemia and low-density lipoprotein. The prevalence of nonalcoholic fatty liver in obese children is also higher. In addition, the risk of obese children's blood pressure exceeding the normal range of blood pressure in this age group is 1.79 times higher. Although obese children may not suffer from hypertension in childhood, they have a higher risk of hypertension in adulthood. The mental health problems of obese children can not be ignored. Damaged self-image will undoubtedly affect self-esteem, produce negative emotions and avoid social activities, resulting in a higher incidence of bad behavior. Obese children are prone to psychological and behavioral disorders, including aversion, irritability, distraction, low response threshold, impaired self-awareness, low self-evaluation, unsociable, unhappy and dissatisfied, poor social adaptability and so on. Many parents will have this question: how fat is the child and need to see a doctor? Do you need to see a doctor until you are severely obese or affect your development? Or do you have to go to the hospital as long as you are overweight or obese? In fact, not all individuals with the same degree of obesity have the same cardiovascular metabolic risk. Children's weight and metabolic state have certain plasticity. Some children will reduce or alleviate the degree of obesity in adolescence. Nowadays, the obesity screening method has changed from the high and low classification of body mass index (BMI) in the past to the classification according to metabolic abnormalities. Childhood and adolescent obesity can be divided into metabolic healthy obesity, metabolic abnormal obesity and metabolic obesity with normal weight. Metabolic obesity refers to the combination of at least one metabolic abnormality on the basis of obesity. The abnormal factors include elevated blood pressure, abnormal blood glucose, abnormal blood lipid and insulin resistance, which is the key point in the treatment of childhood obesity. It is suggested to monitor the growth and development of all children and adolescents, and regularly check their height and weight, so that children and adolescents can grow at a reasonable growth rate. Different obesity screening strategies are adopted for children and adolescents of different ages. Children aged 6-10 years are found to be obese, and the health care doctor asks the medical history and carries out physical examination. Screen for obesity or overweight caused by lifestyle, psychology, sleep and other factors. Health care doctors regularly monitor the degree of obesity, and timely educate and remind parents to correct these adverse factors. If there are children with abnormal intellectual development, congenital malformations, growth retardation, headache, visual field defect, black acanthosis, purple lines, dwarfism, low posterior hairline, cervical webbing, abnormal development of secondary sexual characteristics, or the degree of obesity continues to increase rapidly, it is recommended to go to the hospital to screen for secondary obesity. Children and adolescents aged 10-18 continue to be overweight, so it is recommended to screen for metabolic obesity. The incidence of metabolic abnormalities, the incidence of cardiovascular disease and type 2 diabetes increased significantly in adults. Go to medical institutions to check blood lipid, blood glucose and blood pressure, find corresponding abnormalities as soon as possible, actively treat them, and recheck them at least once a year. There are some common endocrine diseases, nervous system diseases and genetic syndrome in children. Obesity is often one of its symptoms and needs further examination and treatment. For example, congenital hypothyroidism, small fat Wiley syndrome, although the incidence rate is not high, accounting for only 3% to 5% of children obesity, but due to the great harm, parents should pay enough attention to it. (outlook new era)