Abstract: Mandibular defect reconstruction is a synthesis subject which integrates rapid prototyping, CT scanning and image processing, 3D reconstruction and so on. After the mandibular of factually defected case was modeled with software and reconstructed with fibular, the personal mandibular can be manufactured with RP machine to ensure the best operation affection. Image processing was executed directly on DICOM files scanned from spiral CT, where CT image processing technology was used to separate mandible by the operation of threshold, region growing, masks editing, calculating and so on. Then, fibular STL files were imported into software to fit with the mandible defect region, and the three dimensional model of reconstructed mandible was obtained by model reconstruction and optimization.