Objective To evaluate the clinical application and effect of computerized digital sur -gical assisted design and manufacture for reconstruction of mandibular defect with vascularied iliac crest flap graft .Methods CT was used to scan the craniofacial and maxillofacial region of mandibular ameloblastoma patient ,and then the 3D model of the maxillofacial skeleton was reconstructed using the computerized digital surgical aid design to simulate the focal resection and the mandibular defect reconstruction with the iliac crest flap .Surgical guides were prepared by 3D printing to assist focal re-section and bone reshaping .Postoperatively ,clinical and CT examinations were performed to observe the restoration of the patient's facial appearance and occlusal relationship ,as well as wound healing and graft survival .Results Postoperative review results showed that the bone graft survived well ,and the anastomosed bone was formed .The wound in the surgery area healed .No recurrence of the tumor was found after clinical and CT examination .The maxillofacial appearance was well restored ,and the re-sidual occlusal relationship recovered well .Conclusions The use of computerized digital surgical aided design combined with 3D printing technology can effectively simplify the mandibular segmental defect repair and reconstruction and optimize the postoperative repair effect .