Obesity, defined as a certain degree of significant overweight with a thick layer of fat, is a state caused by the accumulation of too much body fat, especially triglycerides. Obesity is a disease characterized by increased body fat content, often combined with fatty liver, hyperlipidemia, atherosclerosis, coronary heart disease and type II diabetes prompting death. Obesity in childhood can be the precursor disease of adult obesity, hypertension, coronary heart disease and diabetes, etc. Therefore, it is a chronic metabolic abnormal disease, so it should be paid attention to and early prevention. In our country, about 70%~80% of children obesity will continue to become adult obesity, so we need to understand the knowledge of childhood obesity. First of all, let’s understand the standard of judging obesity. The standard of childhood obesity generally refers to the weight exceeds 2 standard deviations of the average weight of healthy children of the same sex and age or healthy children of the same height; or exceeds 20% of the average weight of the same age and sex. For example, a 1-week-old boy with a measured weight of 14.1kg, while the standard weight of boys at this age is 10.05kg and +2SD is 12.54kg, so this child has reached the diagnostic standard of obesity. Obesity is divided into three categories: (1) simple obesity: accounting for more than 95%, mainly caused by genetic factors and excessive nutrition. Closely related to lifestyle, it is a chronic disease characterized by excessive nutrition, insufficient exercise and behavioral deviation. (2) secondary obesity: caused by endocrine disorders or metabolic disorders, the incidence is low, accounting for about 1%. This kind of obesity needs to be treated by doctors’ medical intervention. (3) drug obesity: it is a kind of secondary obesity, due to long-term use of some drugs caused by obesity performance, the most common is the use of long-term use of a large number of glucocorticoids caused by obesity, but generally after stopping drugs obesity will gradually disappear. Obesity grading: more than 10% of the same age weight for overweight, 20% for mild obesity, more than 30% for moderate, more than 50% for severe obesity, more than 100% for serious obesity. Because of the different height of children, the influence of weight is great, so the body mass index (BMI) [8], that is, kg/m2 (kg for weight, m for height) should be used as the standard. 2000 February WHO Western Pacific region obesity working group proposed the standard of Asian adult body mass index: BMI 18.8~22.9 for normal, <18.5 for low weight, ≥23.0 for overweight. 25.0-29.9 is mild obesity, and ≥30.0 is severe obesity, but in children, depending on age, bmi values ≥85% are considered overweight and ≥95% are diagnosed as obese. < p=""> The causes of simple obesity are complex, with genetic influences, environmental factors, and individual physical characteristics. There are three high incidence periods of childhood obesity: (1) infancy (2) school age (3) adolescence. Infancy is mainly due to the relatively small range of activities and intensity, children cry as soon as the family is fed, increased intake, resulting in obesity. However, most obesity improves after 2-3 years of age, but some can continue to develop into adulthood. Above moderate simple obesity of school-age children, the age of beginning to gain weight is mostly around 7 years old, mainly related to fast eating, excessive intake of carbohydrates and lipids, and reduced activity. Obesity has certain family inheritance tendency: both parents are fat, 70%~80% of the offspring appear obese; one of the two parents is obese, 40%~50% of the offspring are obese; both parents are not obese, nearly 1% of the offspring appear obese; monozygotic twins also have very high rate of the same disease. The treatment of simple obesity in children, the main thing is diet control, followed by exercise, too fat need to be treated with drugs, the key lies in their own determination and the supervision and cooperation of parents. At present, the international weight loss follows three principles, namely, no anorexia, no weakness, no diarrhea. Secondary obesity is mainly treated for the primary disease. Treatment of childhood obesity: (1) control diet (2) increase exercise (3) behavior therapy (4) medication (5) Chinese herbal medicine. Obesity is focused on prevention. Including: 1) Avoid over-nutrition and excessive weight gain of the mother during pregnancy. 2) Perinatal health care should include guidance on infant feeding, emphasize the benefits of breastfeeding, give specific guidance on breastfeeding, and publicize the dangers of overfeeding. During infancy, exclusive breastfeeding is encouraged for 4-6 months.3. No solid food is added for the first 4 months after birth. Measure and record the weight every month, and if the baby is found to be gaining weight too fast, give timely guidance to the mother to give less and later solid food, especially cereals, and replace them with fruits and vegetables. 4.In the early years of the baby, we should cultivate good eating habits, establish a regular living system, and avoid overfeeding and overprotection. 5.For school-age children and adolescents, fat children’s self-awareness and self-control gradually improve. It is important to strengthen nutrition education and health education, promote nutrition knowledge, guide correct food choices, encourage more fruits and vegetables, and remove or reduce fatty and sugary food components in the diet. 6.Perform at least 30 minutes of moderate intensity sports or physical activities every day. 7.Control the time of watching TV and playing video games and reduce the academic load. 8.For children who are already obese and potentially obese, we should Carry out comprehensive interventions including diet modification, exercise prescription, behavior improvement, tracking and monitoring and clinical treatment, but do not advocate starvation, surgery, physical therapy and short-term rapid weight loss.