If there is a long-term daytime low fever and normal body temperature at night, we should first rule out any afternoon low fever or night sweats. If bacterial or viral infection is ruled out, it is necessary to consider whether there is any hematologic or tumor-related disease, which requires us to improve the blood routine, C-reactive protein, and related tumor and immunologic tests. If the diagnosis is clear that it is tuberculosis, it is necessary to go to a professional treatment facility such as a tuberculosis clinic for timely treatment, and if there are blood and tumor diseases, further consultation and treatment can be conducted. In conclusion, if you have a recurring chronic daytime low fever, you must get a clear diagnosis in time so that you can treat it earlier.