There are many reasons for children’s low fever not to go down, such as streptococcal infection, tuberculosis, blood diseases and other diseases. 1. Streptococcal infection: if children usually have a relatively poor physical condition and weakened resistance, it will induce bacterial infection, and the baby will have the manifestation of scarlet fever, resulting in the appearance of low fever, and need to check the anti-streptococcal O and urine routine in time, to avoid aggravation of the condition. 2. Tuberculosis: Inhalation of Mycobacterium tuberculosis from the respiratory tract into the human lungs leads to infection of the lungs, which causes tuberculosis. Babies will show symptoms such as emaciation, night sweating (abnormal sweating after going to sleep, and the sweating stops after waking up), and recurrent low-grade fever, etc. They should be checked in time in the hospital by PPD test and chest radiographs. 3. Blood disease: Due to the abnormality of hematopoietic system, the number of cells, cytokines and functions in the blood change, thus causing blood disease, which will cause low fever, fatigue, weakness, etc. It is recommended to go to the hospital in time to check the blood routine and clarify the cause. There are many other causes of low fever in children, and it is recommended to actively seek medical attention and be evaluated and treated by a specialist.