Abstract: There were many reports on the effects of condylar fracture on TMJ, but no report about bone density and biomechanical changes of condyle after condylar fracture. In this study, the effects of longitudinal condylar fracture on TMJ in the childhood miniature pig were observed by using “DEXA” and “biological mechanics” methods. The results showed: longitudinal fractue apparently decreased the condylar bone density and mechanical function.