Sheng Jiaxin's mandibular angle surgery refers to the principle of fine grinding and cutting after long curve osteotomy of mandibular angle, curved surface resection of external bone plate to adjust bone thickness (if the chin is too wide, it will cooperate with T-bone fracture of chin). Therefore, compared with the traditional mandibular angle, the operation of St. Jia's new mandibular angle is more suitable for all kinds of mandibular angles, and the frontal and lateral effects can be maximized.