Fever is the most common symptom in pediatric clinics, and the etiology and treatment of children who always have fever and are mainly at night are analyzed as follows: First, fever is divided into fever for more than 7 consecutive days according to the length of time is called long-term fever, if the child is a long-term fever, whether daytime or nighttime, its common causes are pathogenic infections, especially atypical pathogens, such as mycoplasma, tuberculosis, in addition to immune system diseases, such as juvenile Idiopathic arthritis generalized type, Kawasaki disease, etc., need to go to the hospital to perform relevant tests to clarify; Second, if the child’s fever is less than 7 days, that is, acute fever, the common causes are viral infections, common bacterial infections, such as influenza, urinary tract infections, respiratory tract infections, which are generally self-limiting and will get better on their own after 3-5 days, except for urinary tract infections, which need to be treated with antibiotics at this time. If the fever temperature exceeds 38.5 ℃ or more need to take antipyretic drugs, such as ibuprofen or acetaminophen. The fever is worse in the afternoon or evening after the child has the disease, and the fever is lighter in the morning.