Abstract: Objective：To compare the hyoid bone position in patients with the Unilateral Cleft Lip and Palate(UCLP) following the orthodontic treatment. Methods: 20 UCLP patients with crossbite of anterior teeth were included in this study. There were 15 male and 5 female patients,with average age 18.60±4.72 years. Lateral cephalogram were taken for each patient before and after treatment. 6 measurements were carried out to find the changes of the hyoid. The paired t test was used to evaluate the changes of the hyoid bond. Result: H-PTRper(mm) and H-Sper(mm) increased significantly（P＜0.05）after the orthodontic treatment. Other measurements had no significant changed after treatment. Conclusion: The anteroposterior position of the hyoid bone was significantly backward after orthodontic treatment There were no significant changes of the vertical position and the axial inclination of the hyoid

Key words: Unilateral cleft lip, palatehyoid position, Orthodontic treatment, Cephalometrics, Class Ⅲ elastics Crossbite