Objective: The free fibula flap is widely used for reconstruction of mandibular defects.However, the three-dimensional position of the fibula flap is very difficult to control during the operation only according to the experience of the surgeons.The purpose of this study is to improve the process by using computer-aided design and surgical navigation.Methods: 24 cases with primary unilateral mandibular reconstruction with free fibula flap in Peking University School and Hospital of Stomatology from June 2013 to December 2013 were reviewed.The cases were divided into 3 groups.8 cases in Group A were operated traditionally by the experience of the surgeons, 8 cases in Group B were carried out computer-aided design alone before the operation, and both computer-aided design and surgical navigation were used in the other 8 cases of Group C.The position and angle of the reconstructed mandibular angle were evaluated by comparing preoperative and postoperative computed tomographic data.The operation time of each case was recorded.The data was statistically analyzed with SPSS 13.0.