The method comprises steps of making a plaster dental cast of a patient, reconstructing jaw image assembly models, performing registration between physical stone and image model, adjusting the plaster dental cast based on a x-ray cephalometric plan, tracking movements of the plaster dental cast, obtaining optimal symmetry planes of the upper and lower jaw image assemblies, determining whether a degree of overall symmetry is elevated, and making surgical occlusal splints for surgical guiding. With foregoing method, possible results of executing an orthognathic surgical plan can be predicted and the surgical plan can be considered more carefully to achieve both occlusion function and facial symmetry.