Operation method: 1. Extraoral incision: make a 3-5 cm incision in the mandibular angle to remove the mandibular angle; 2. Postauricular incision: make a 3-4 cm incision behind the ear to remove the mandibular angle; 3. Combined incision inside and outside the mouth: a 3 cm ~ 4 cm incision is made in the mouth and two 0.5 cm ~ 0.8 cm incisions are made under the mandible, which can very conveniently remove the hypertrophic mandibular angle, at the same time, the mandibular outer plate and mandibular margin can be removed, and part of the masseter muscle can be removed; 4. Submandibular micro-incision: it is to use the combined incision inside and outside the mouth to insert a 0.5 cm ~ 0.8 cm micro-incision of the chainsaw to complete the whole operation process. The incision is under the mandible and will not be obvious after 3 ~ 6 months; 5, complete intraoral incision: it is the best surgical method at present. It is to use a 3 cm ~ 4 cm incision in the oral cavity to cut off the hypertrophic mandibular angle, and at the same time, it can cut off or grind off the mandibular outer plate and mandibular margin, and can cut off part of the masseter muscle.