Down's syndrome (DS) has been shown to be associated with many neurological complications, including cognitive deficits, seizures, early-onset dementia that resembles Alzheimer's disease, and neurological complications of systemic disorders. DS patients show to have poor performance in executive functions (EF) and fine motor skills. In this study, we examined the brain hemodynamic responses and brain activation patterns of DS children during the completion of EF tasks. Revealing its neural mechanism of DS is not only able to contribute to the early intervention of this children with DS, but also increase understanding of developmental cascades in childhood.