OSAHS is a common disease during sleep and its pathogenesis is complex.The anatomic level of upper airway is a more recognized pathogenic factor.Recent studies have shown that nonanatomic factors,such as insufficiency in dilation muscles of upper airway,high loop gain and low arousal threshold,play an important role in the pathogenesis of OSAHS.This paper revives the latest literature home and abroad on the anatomical and nonanatomical factors in the pathogenesis of OSAHS and makes a systemic review.