If the belly button of a child born 40 days old protrudes, the most common type of hernia is an umbilical hernia, which is a round protrusion with a relatively smooth surface that can be retracted by pressure, and sometimes the sound of air passing through water can be heard. Umbilical hernia is formed mainly because of the imperfect development of the abdominal wall and the local protrusion of the intestinal canal. The base of umbilical hernia is relatively wide and it is relatively safe as strangulation or intussusception rarely occurs. Umbilical hernia does not require special treatment in the early stage, but it will increase significantly when exerting force or crying, so avoid exerting force or crying as much as possible. Generally, the umbilical hernia will heal on its own when it is about one year old, but if it does not heal at one and a half years old, it should be treated surgically in pediatric surgery.