The jaw bone is located at the bottom of the face and is the main component of the lower third of the face. The jaw angle is an important factor in determining the shape of the face. Oriental women are beautiful with oval or melon shaped face, if the jaw angle is enlarged it will make the face square, which is considered to be lack of femininity and femininity. Therefore, jaw angle osteotomy is gradually carried out, and jaw angle osteotomy has become an important element of facial plastic surgery. At present, the clinical application of the procedure has four types of surgery, such as mandibular angle area full osteotomy, mandibular outer plate sagittal osteotomy, joint use of angle area osteotomy and mandibular outer plate sagittal osteotomy, and mandibular bone grinding. If the osteotomy line is not designed properly, complications such as injury to the second mandibular angle, neurovascular bundle in the mandibular canal, asymmetry on both sides and mandibular neck fracture will occur after surgery. The highest complication rates in mandibular angle osteotomy are: uncoordinated osteotomy line (80%), bilateral asymmetry (16%), chin nerve injury (1.8%), and intraoperative hemorrhage (1.5%). Each type of surgery has its own advantages and disadvantages, and the treating surgeon should adopt a specific method for each case to obtain the individual jaw angle shape. In the process of revealing the mandibular canal, it was found that the lateral plate of the mandible is composed of thick dense bone, which is dense and hard and difficult to saw. The lateral plate passes through a thin layer of osteophyte and reaches the wall of the mandibular canal, which is a thin layer of osteophyte. The design of the curved osteotomy line The jaw angle osteotomy is not to eliminate the jaw angle, but to make the curve of the jaw angle more smooth and natural, more in line with the aesthetic requirements. The osteotomy should also consider the individual needs of the candidate. III. Clinical significance 1. Practical: At present, the X-ray is the preferred clinical reference for jaw angle surgery, and the removal of specific bone volume still mainly depends on the experience of the operator. The design of this osteotomy line can turn the vague practice of relying on experience into scientific and quantitative. Since the ratio of the skull to the X-ray is about 1:1, the design of the osteotomy line on the mandibular X-ray before surgery is equivalent to the design of the osteotomy line on the surface of the mandible. By inputting the X-ray of the patient’s head into the computer before surgery, a perfect curved osteotomy line can be designed by this method with the help of drawing tools, and then communicating directly with the patient, the best satisfaction can be achieved and medical disputes can be minimized. The design of the osteotomy line is determined with the help of living mark, and this osteotomy line designed according to the anatomical characteristics of the mandible has the advantages of obvious mark, easy to operate and easy to promote. 2.Safety: The mandibular canal is an arc, and the three osteotomy lines are below the mandibular canal, which is basically parallel to the mandibular canal, and the distance from the mandibular canal is more than 5mm, which will not damage the vascular nerve in the mandibular canal, and will not significantly reduce the biting force of the mandible. Factors such as the degree of jaw angle hypertrophy, the distance of the mandibular canal from the jaw angle, and the degree of proposed reduction of the lower part after surgery determine the width of the osteotomy, and the amputation of the jaw angle can achieve the purpose of significantly improving the face shape, and should not be too wide. 3.Aesthetics: the two ends of the osteotomy line are left with curved lines, and the edges of the mandible are smooth and natural; the appearance of the second mandibular angle after straight-line osteotomy and triangular block osteotomy is effectively avoided. With the amount of bone retained as the measure, a wider jaw angle can be amputated within a safe range to obtain the maximum symmetrical and cosmetic effect. It avoids excessive or insufficient bone cutting on both sides and asymmetry, and overcomes disadvantages such as the width of bone cutting is not easy to grasp with other osteotomy methods.