Abstract: Objective: To investigate the clinical efficacy of implants individualized by three dimensional printing technology in reconstruction of mandibular defects. Methods: Included in this study were three patients with segmental defects of mandible. The digital data of three dimensional mandibular model were obtained by spiral CT. In two out of three cases, a resin model of mandible was made by 3D printing technology and then the titanium plate for reconstruction was individualized according to the resin model before operation. In the rest one case, the digital data of the implant were carefully designed before operation, and directly inputted into the three dimensional printing machine so that an individualized implant with condyle was manufactured. The lesion segment in mandible was resected according to pre-operation design, and meanwhile the printed implant or ilia graft was planted. Results: In application of three dimensional printing technology in reconstructing mandibular defects, customized implants fitted the defects smoothly; the operations became much easier; bone remodeling became quicker and more accurate. All patients were followed up for 3-11 months, and they were satisfied with the aesthetic outcome. Meanwhile stable occlusions were gained and no loosening, displacing or losing of the plant was found. Conclusion: Application of three dimensional printing technology to repair mandibular defects can not only shorten the operation time, reduce the surgical trauma, but also improve the accuracy of mandibular reconstruction, and achieve both aesthetics and function at the same time, which provides a fast and effective method for the simulated reconstruction of mandible.