The first thing you need to do is to go to a psychiatric hospital and see a specialist to correct it as soon as possible. 2, parents should try to reduce the attention to the child’s nail biting behavior, such as: blame, criticism, and even scolding. Let the child try to grow up in a relatively safe, calm and comfortable environment. Try to guide, to encourage, to affirm, to give more correct guidance. The best children grow up in the sound of praise, so that their self-confidence is constantly strengthened. 3, expand the child’s social range, so that they have more contact with peers, so that the child can learn more suitable for his psychological age, physical age social skills, conducive to the child’s mental health, as well as the formation of a sound personality. 4, usually pay attention to observe the child’s flash point, to see in which areas of talent and interest, can focus on cultivation. 5, increase the number of children’s talent and interest. 5. increase outdoor activities to divert his attention and keep a happy mood. 6. develop a good habit of regular nail trimming. 7. pay attention to dietary regulation, avoiding the bad eating habits of partiality and a balanced diet. To protect nutrition, especially to avoid deficiencies of zinc, iron, etc.