There are relatively well-designed preoperative and predictive procedures before orthognathic surgery, and the surgeon and the patient can communicate the change in postoperative shape more visually before the surgery through the postoperative outcome prediction chart. However, there is no exact correlation between the amount of chin anterior migration, the amount of chromogenic airway augmentation, and the degree of OSAHS remission because there are very complex functional, morphological, and pathological and physiological regulatory mechanisms between the above three. Therefore, it is not possible to predict the outcome of OSAHS treatment preoperatively. Postoperative guidance: 1. About numbness and discomfort of the lip and chin Even if the chin nerve is not cut, the chin nerve will inevitably be stretched during surgery, and therefore numbness and discomfort of the lip and chin will occur. Most of the patients’ discomfort is temporary and recovers within 3 to 6 months after surgery. In a few patients, the discomfort is permanent or only partially recovered. This point must be repeatedly explained to the patient before the surgery. 2, about the change of the postoperative shape substantial front migration chin basic surgery and “convex” osteotomy certainly make the chin receding deformity patient’s face shape occurred more obvious change. However, this change must take some time before the final result is achieved. On the one hand, there is a relatively obvious soft tissue swelling in the short term after surgery, and on the other hand, there is a process of healing and reconstruction of the bone segment after the osteotomy. Generally, the facial shape can be more stable only about one year after surgery. As mentioned before, no significant correlation has been found between the anterior displacement of the tongue root, the opening of the upper airway and the relief of OSAHS; the reduction of OSAHS symptoms will gradually improve with the reduction of postoperative swelling and the improvement of respiratory regulation mechanism. It is recommended that postoperative PSG review should be performed at least one month after surgery. 4. Regarding the problems that should be paid attention to by the postoperative patients 3~5 days after surgery, the patients should mainly eat liquid food, and within one month after surgery, in order to avoid accidental fracture of the mandible, they should eat semi-liquid food or diet. After eating, attention should be paid to oral hygiene to prevent infection of the intraoral wound. Oral rinsing should be routinely completed twice daily by the nurse within 5 days after surgery. Patients are encouraged to resume brushing their teeth as soon as possible, but care should be taken to protect the intraoral wound. Every care should be taken to avoid trauma to the face within six months after surgery.