Obstructive sleep apnea (OSA) is a disease characterized by repeated partial or complete upper airway collapse during sleep, accompanied by arousals or oxygen desaturation. It was reported to affect 5.7 %~9.6 % of pediatric population in western countries and 5.5 %~7.8 % in China. Children's physical developing and brain functioning as well as quality of life (QoL) could be greatly impaired if the disease was left untreated.