DNA methylation is one of the most commonly recognized epigenetic phenomenon, which explains how genes, environmental factors and gene-environment interaction would cause obesity, integretedly. Studies on early life obesity-related epigenetic reveal important effects that related to the programs on prevention and control of obesity. However, only few similar studies have been conducted in China. This paper summarizes the basic principles, characteristics of DNA methylation and the major results of children and adolescents obesity-related research areas, in order to provide evidence for further studies.