The term “face deviation” mainly refers to the asymmetry between the left and right side of the face. Sometimes, it can be accompanied by deformities such as cheekbones of different heights, eyes not in the same plane, and a crooked nose. The causes of “face deviation” are rather complex. Developmental abnormalities are the most important cause of facial asymmetry. Developmental abnormalities can be soft tissue or bone tissue. Previous studies have found that the joints on both sides of the chin, medically known as the temporomandibular joint, are an important growth center for the facial skeleton. If the joints on both sides do not develop to the same degree, the face will be skewed, with the faster growing side having a larger face and the opposite side smaller, and the chin may be skewed toward the slower growing side, while the upper jaw will also be skewed and cause a skew in the plane of the teeth. The main factor affecting joint development is heredity. In addition, trauma is also important, such as injury to one side of the joint due to a fall, which may cause impaired joint development on that side. Some bad habits such as chewing on the lateral side may also have some effect on the development of the joint. In addition, some inflammatory, proliferative and tumor diseases in the joint area may also affect the development of the facial bones to varying degrees. Sometimes facial asymmetry involves other facial bones such as orbits, nose, cheekbones, etc. This is also mainly due to the uncoordinated development of the facial bones on both sides. There are also some rare congenital diseases, such as gill arch syndrome and hemifacial atrophy, which can be accompanied by “facial deviation”, and their severity varies. Usually, the treatment of facial asymmetry is complicated and requires careful and comprehensive preoperative examination to identify the cause of the “face deviation”, and most patients require surgical treatment.