Abstract: Objective To investigate the clinical efficacy of treatment of mandibular old fractures. Method From April 2010 to May 2013, 11 cases of mandibular old fractures were treated with Orthognathic surgery and rigid internal fixation. According to the imaging data, model of surgical,Osteotomy site and rigid internal fixation were taken to restore normal occlusion. Fracture healing were evaluated by the X-ray and Clinical efficacy by Occlusion , bite force and joint mouth of the inferior temporal postoperatively. Result Fractures healed six months postoperatively by X-ray. Occlusion , bite force and infratemporal joint is good. One patient , although the degree of mouth and face shape is good, poor bite joints,was treated by Orthodontics Orthotics after internal fixation for eight months. Overall patients excellent rate of is 90.9%.. Conclusion Orthognathic surgical techniques and rigid internal fixation of mandibular fractures provide secondary anatomical reduction and get a reliable guarantee for restoration of normal occlusion , open-closed function and facial appearance.