Children are in the growth stage and falls to the back of the head are more common, and the risk period for children falling to the back of the head is 72 hours. Children’s back of the head is relatively fragile, and a fall may cause concussion, cerebellar hemorrhage, cerebellar contusions and other conditions. When a child falls on the back of the head, parents must closely observe the mental state, observe whether there is drowsiness, nausea, vomiting, irritability, mental atrophy, dizziness, headache, jet vomiting, etc. Usually brain injury will appear within 24 hours of symptoms. If there are no such symptoms, it still needs to be observed for about 24-72 hours. If the child does not have any abnormal reaction for more than 72 hours, it can indicate that the danger period has passed. If a child falls on the back of the head with nausea, vomiting and other symptoms, parents must immediately take the child to the hospital emergency department to avoid serious consequences.