A child’s sudden cleanliness may be related to psychological factors, family and social factors, and genetic factors. 1. Psychological factors: cleanliness is a psychological disease, belongs to obsessive-compulsive neurosis, usually with obsessive-compulsive personality patients will show cleanliness. 2. Family and social factors: In the environment of family or school, those who have the behavior of cleanliness will have certain influence on the children’s cleanliness. At the same time, if the pressure from the family or the school is too much, the child will also show cleanliness behavior. 3. Genetic factors: Some studies have shown that children with cleanliness behavior in their family will have an increased likelihood of developing cleanliness. Suddenly children with cleanliness should be given the correct consciousness and behavioral guidance to find out the causes of cleanliness, patiently correct the behavior, parents can consult a doctor if necessary.