The key is to adopt the method of oral incision: the mandible can be modified through oral incision, and some bones or prostheses to be removed can be placed in a certain part of the mandible to change the shape of the mandible. It has the advantages of less surgical trauma and no trace on the face after operation. It is widely used in clinic. Mandibular angle long curve osteotomy is a one-time osteotomy, which makes an incision in the oral mucosa, adopts advanced endoscope-assisted technology and uses a special surgical saw to form a one-time osteotomy from above the angled mandibular angle to below the vertical line of the corner of the mouth.