Fever is a common symptom in children, many diseases can cause fever, due to the imperfect development of the central nervous system in children, once the fever is easy to cause high fever does not go away, usually the oral surface temperature > 39 ℃, or anal surface temperature > 39.5 ℃ as high fever, ≥ 41 ℃ as ultra-high fever. High fever can bring harm to the baby’s organism, such as causing febrile convulsions, increased oxygen consumption, existing hypoxic baby can aggravate tissue hypoxia, fever can cause an increase in cardiac output, so that heart disease, anemia baby’s heart burden increased or even cause heart failure. High fever can aggravate the intracranial pressure, so high fever always needs to go to the hospital early to find the cause of the disease, for the cause of intervention treatment.