Fever due to connective tissue disease is usually characterized by a long course of irregular fever, which may be persistent, etc., and may be of short or long duration, mostly related to disease activity. It occurs in the early stages of the disease or when the disease is not effectively controlled, or during the course of the disease. Connective tissue diseases that often cause fever are systemic lupus erythematosus (SLE), rheumatoid arthritis, and adult Steele’s disease. 1. Systemic lupus erythematosus (SLE): Patients may have fever as the first symptom, or it may be a concomitant symptom, which manifests as persistent or intermittent fever. Clinical manifestations of low to moderate fever, antibiotic treatment is ineffective, can be relieved by glucocorticoids such as prednisone. 2. Rheumatoid arthritis: low-grade fever may appear during acute attack, which is more insidious and not easy to be detected. A small number of patients may have high fever, it is necessary to determine whether there is a possibility of co-infection, once clear need to carry out anti-infection treatment. 3. Adult Steele’s disease: arthralgia, transient rash, high fever or elevated white blood cells are the main clinical manifestations. The onset of the disease is rapid, and the fever type is usually flaccid fever, mostly above 39℃, and occasionally the fever stays for several days. If the patient’s general condition is good, and there is no obvious toxic symptoms, usually in the fever as normal. Connective tissue disease caused by fever patients need to early hospital consultation, a clear diagnosis, under the guidance of the doctor reasonable use of medication.