Objective: To investigate the influences of retrognathia on upper airway form and hyoid position. Methods: The patients were divided into the retrognathic group and normal group,according to ANB and SNB. CBCT and Dolphin Imaging 11.0 software were used to compare the differences of width and volume of upper airway,angle with cranial base,and the position of hyoid between two groups. Results: Compared with normal group,the measurements of LP3,VOP and VP in retrognathia group are smaller,the angles of oropharynxes are more retroclined,and hyoids positions were lower and more backwards. H-VPS is significantly correlated with LP3,VOP and VP in retrognathia group. Conclusion: The volumes and angles of oropharynxes,and the hyoid positions in retrognathic patients are abnormal.