Abstract Vitamin D (Vit D) deficiency is prevalent worldwide, and the prevalence of childhood obesity is increasing globally. Many studies have supported that Vit D deficiency may be an important cause of childhood obesity, and the level of serum Vit D among obese children decreases,simultaneously. Both Vit D deficiency and obesity among children interact through direct factors, molecular mechanisms and environmental factors, but the mechanism of interaction has not been fully elucidated. In the future, higher level research in evidence based medicine could be conducted to explore the association between childhood obesity and Vit D deficiency and the possible mechanisms of their interaction, in order to provide scientific evidence for the prevention and control of Vit D deficiency and obesity among children.