Repeated fever with normal blood test may be caused by special bacterial and viral infections, malignant tumors and rheumatic immune diseases. 1. Special bacterial and viral infections: if the fever is caused by some special bacteria such as typhoid bacillus, tuberculosis bacillus infection, or viral infections, there may be a normal blood test, or even lower, but the phenomenon of recurrent fever, the patient needs to be further examined for C-reactive protein, hemosiderin and so on. 2. Malignant tumors and rheumatic immune diseases: generally, patients with malignant tumors and rheumatic immune diseases may also have symptoms of recurrent fever, but there may be no obvious abnormality in routine blood tests. There may be other reasons for repeated fevers but normal blood tests, so it is recommended that patients actively seek medical attention to clarify the cause of the disease and then carry out standardized treatment.