Adult obesity has characteristics of high prevalence rate and difficulty of treatment.Simple obesity of children is an important risk factor for adult obesity.Finding outthe cause of children simple obesity and the related influence factors plays at vital role inobesity prevention and control.Obesity is a polygenic inheritance which is an accumulationof several smaller genes, and a jointly result of genetic factors and environmentalfactors.Among numerous genes closely related to obesity, FTO is the first found allelicsusceptibility gene has the strongest relationship with obesity from a genome-wide associationstudy.