Objective:To analyse the asymmetry of mandibular of adults with skeletal classⅢmalocclusion and mandibular deviation using cone-beam computerized tomography(CBCT).Methods:20 adults with skeletal classⅢmalocclusion and mandibular deviation (deviation group)and 20 adults with individual normal occlusion(normal group)were included.CBCT slices were taken for each sub-ject.INVIVO 5 software was used to make 3D reconstruction and location marks for line distance and volume measurements of mandi-ble and condyle.Results:The measurements of the mandibular ramus length,mandibular total length,hemi-mandibular volume, mandibular ramus volume,posterior part of mandibular body length,condylar unit length,angular unit length,body unit length and an-gular angle in deviation group were significantly different between 2 sides(P<0.05).Compared with the normal group,differences of the asymmetry of mandibular ramus length,mandibular total length,hemi-mandibular volume,mandibular ramus volume,posterior part of mandibular body length,angular angle,condylar unit length and body unit length between 2 sides in deviation group were sig-nificantly different(P<0.05).Conclusion:In adults with skeletal classⅢmalocclusion and mandibular deviation deviated condylar and mandibular ramus are smaller than those of the nondeviated;the posterior part of mandibular body is slightly asymmetric while the anterior part of mandibular body is almost symmetric.