It is recommended to observe the baby for 1-3 days after bumping the back of the head, including various manifestations such as mental, diet and behavior, and the specific observation time varies according to individual circumstances. If there is no obvious trauma to the back of the head, and there is no significant abnormality in mental, diet and behavior as usual, you can observe at home for 1-3 days first; if there is visible head trauma, such as redness, swelling, bleeding and laceration, you should go to the hospital in time to prevent infection; if there is vomiting, pain, coma, convulsion, fever, crying and other manifestations different from usual, you should consider skull fracture or intracranial hemorrhage, etc. In case of emergency, it is recommended to go to the hospital immediately for CT or MRI examination of the head to clarify the diagnosis and give corresponding treatment measures as soon as possible. After a baby knocks the back of the head, it is recommended to go to the hospital to improve the relevant examination to understand the injury situation, and if no abnormality is found, it is recommended to observe for at least 72 hours. Parents should usually enhance care measures to reduce the risk of cranial injury to the baby.