After more than ten years of clinical practice in plastic surgery, Dean Huang Dayong found that the beauty of a person's appearance is mainly reflected in the lower part of the face, because there are two S-shaped curves from nose to lips and from lips to chin, which is the part that can best reflect the beauty of facial curves. The length of the face and the shape of the lower half depend on the shape and size of the chin. Therefore, the mandible is of special importance in appearance, and the mandibular angle constitutes the most basic line in facial contour.