Abstract: Objective　To study the effect of skeletal class Ⅲ malocclusion with different vertical facial types on the cranio-lingual plane, so as to provide guidance for clinical treatment.    Methods    Cranial lateral imaging data were collected from 186 patients with Class Ⅲ alocclusion ,and hyoid bone related data were measured using winceph 8.0 software for statistical processing.　Results　Horizontal distance of hyoid bone class Ⅲ malocclusion: low angle> average angle> high angle; Vertical distance of hyoid bone class Ⅲ malocclusion: high angle> average angle> low angle. The high angle of transverse and longitudinal slope was significantly smaller than that of the average angle and low angle.  The latter two were close. There were statistical difference in the vertical distance between the group under 12 years old and other age groups (P<0.05). With the increasing of age, the horizontal and vertical positions of the hyoid bone tended to be constant after 12 years of age. There was no statistical difference in value of horizontal distance and slope among the four different age groups (P>0.05).　Conclusions 　 (1) There is no difference in the horizontal distance of the hyoid bone among people after 4 years of age. The vertical distance shows a little growth change, gradually increases to about 12 years old before the peak period, and no longer changes with the increasing of age. (2) When the vertical bone type is high angle, the vertical distance of the hyoid bone is higher. The lower the mandibular plane is, the larger the horizontal distance tends to.

Key words: Hyoid,  ,  , Skeletal classⅢmalocclusion,  ,  , Vertical facial type,  ,  , Cephalometrics