Children always have fever at night may be related to physiological factors, water intake and other factors, the specific analysis is as follows: 1. Physiological factors: children in the daytime, the body secretes the relevant hormones are more vigorous, the immune system is more active, so the human body can be more effective inhibition of bacteria, viruses, while the relative hormone levels at night is lower than the daytime will be prone to fever. 2. Drinking water: children drink less water at night than during the day, and when the body is dehydrated, it is easier to get a fever, which may also be the reason why children always have a fever at night. 3. Parents did not find in time: children may also be in the daytime fever, just parents did not find, because many children in the daytime even if the fever, but also still can eat and play, the night is quieter, easier to find children with a fever. Children always night fever may have other reasons, it is recommended to go to the hospital in a timely manner to carry out relevant examinations, clear cause of the disease after the positive symptomatic treatment.