Many problems in the oral and maxillofacial area are caused by genetics. Specifically: 1, human evolution from the Yuanmou people to modern humans, the diet structure from the original hair to drink blood to the current food more and more fine, will cause the jaw bone by the chewing function of stimulation, is slowly degraded. In the process of degeneration, the jawbone degenerates, but the teeth do not degenerate as fast as the jawbone degenerates, so from the perspective of human genetics, the misalignment of teeth is caused by genetics; 2, for individuals, the size and shape of each person’s jawbone will be affected by the size and shape of the parents’ jawbone. If the mother and father have malocclusion, the possibility of the child having malocclusion will increase; 3. In addition to genetic factors, environmental factors also have a great impact on the development of the mouth and jaw. Nowadays, children eat more and more fine food, without strong chewing stimulation, the development of jawbone will be limited, but the number of teeth is certain, it will cause certain teeth misalignment; in addition, some children will have bad habits, such as biting fingers, chewing pencils, these local force stimulation, can cause the occurrence of teeth misalignment.