In the child’s teething, tooth replacement, many parents are worried about the child’s teeth grow out of alignment, once the child’s teeth do not grow well to do orthodontics, not to mention the cost, the child has to suffer a lot of suffering. Malocclusion is a developmental malformation, the cause is more complex, generally caused by genetic factors and environmental factors. According to the survey statistics, 60%-70% of the misalignment is caused by acquired environmental factors, so some misalignment can be prevented, the main should do the following: from eugenics to solve the misalignment caused by genetics. Pay attention to maternal nutritional care and prevention of maternal diseases, which are prerequisites to ensure normal fetal development. Prevent trauma during delivery when the fetus is born. Pay attention to the feeding of infants and young children. It is very important to feed infants and children properly and to adopt the correct feeding posture. Advocate breastfeeding, artificial feeding, it is best to use a pacifier similar to the mother’s nipple, the opening of the pacifier should not be too large, the diameter of 1-2 mm is appropriate. When artificial feeding, attention should be paid to the position of the bottle and the feeding posture to prevent the infant’s jaw from being under-extended or over-extended. After children are able to chew food, they should eat slightly hard, easily digestible food to exercise the chewing muscles and promote the development of the chewing organs. Eating foods with a certain degree of hardness can increase chewing function and promote dental and maxillofacial development. Pay attention to the physical and mental health of infants, strengthen nutrition and pay attention to oral hygiene, timely detection and treatment of systemic diseases, such as rickets, indigestion, endocrine disorders and chronic inflammation of the nasopharynx, etc. Oral diseases should also be treated as early as possible: early filling of dental caries, timely extraction of unlossed retained milk teeth, etc. Correct the bad habits of infants and children. The first thing is to remove the cause of bad habits. For the bad habits that occur soon and last for a short time, it is not difficult to correct them through parents’ guidance, reminding and patient persuasion. If necessary, various bad habit breakers are used to help children overcome bad habits. Different malocclusions have different optimal treatment periods, so consult with a professional orthodontist. Early treatment is required for malocclusions that may affect jaw development (e.g., retrognathism and bad oral habits). The treatment of milk teeth retrusion is usually started when the patient is 3-4 years old with a movable aligner and can usually be corrected in 3-6 months, but some patients will relapse during the period of tooth replacement or early permanent teeth and need to be closely observed. Bad oral habits such as lower lip sucking, nail biting, thumb eating, etc. need to be interrupted as soon as they are detected. In the period of tooth replacement, such as retrusion, jaw recession, bad oral habits, etc. should be treated early, rather than waiting until all teeth are replaced. Most malocclusions can be corrected in the early permanent dentition, usually around 11-13 years old for girls and 12-15 years old for boys. At this time, the permanent tooth row is basically established, the craniomaxillary surface still has some potential, good metabolic function, the most significant effect of tooth movement, so this period is orthodontic orthodontic treatment “s golden period. For serious bony malocclusion, it is necessary to wait until full development and maturity (about 18-20 years old) for orthognathic surgical treatment to achieve satisfactory results.