Abstract: Objective To observe the influence of different of body composition on children bone developing.Methods Four hundrend and eleven children aged 8 and 10 with different body composition were studied.According to body fat percent,they were divided into three groups(obese,mediate and thin),then all children were pair matched by height,weight and secondary sexual character.The bone age difference of three groups was observed and compared.A correlation study was done to study the relationship of bone age and body composition in boys and girls.Results Bone age of obese,children was higher than that of thin children.Bone age had the positive relationship with body fat percent,lean body weight and body fat.Conclusion Bo dycomposition exist certain effect on childrens bone development.