Objective To analyze the effects of mandibular Osteotomy based on the Orient Classical Beauty Analysis Mask on the functions of mandibular bone and joint.Meanwhile a precise and quick method of the finite element(FE) modeling before the mandibular osteotomy was developed.Methods The CT data from the same patient pre-and post-mandibular osteotomy were obtained and imported into the ScanIP Module(Simpleware, Simpleware LTD., Exeter, UK).And after the segmentation of the interest regions, the two 3D geometrical models were built up, respectively.Then high-quality meshing was performed in the ScanFE module and the two corresponding FE models were solved in the ANSYS to obtain each stress status under the same loading.Results the 3D FE models including mandible and mandibular joint were created successfully, which kept the accurate anatomical shape.By the configuring material properties, setting the boundary conditions and loading the forces on the different areas, the mechanical status of the models under different loading conditions were simulated and shown to be un-similar.Conclusion There were obvious changes on the patient's joint functions after the mandibular Osteotomy based on Orient Classical Beauty Analysis Mask.The 3D FE modeling software Simpleware and other FE analysis solvers could be integrated to make the biomechanical analysis and the pre-operation plan.