Connective tissue disease refers to a group of diseases that mainly affect the connective tissues of the body, with multi-system and multi-organ involvement of joints, muscles, skin, mucous membranes, blood vessels, lungs, kidneys, and nerves. The cause and pathogenesis of connective tissue diseases are still unclear, and genetic, pathogenic infections, sex hormones, and environmental factors may be associated with the development. Connective tissue disease has a long and complex course and is prone to combined multi-system and multi-organ injury. Because of immune abnormalities in connective tissue diseases, clinical manifestations such as fever, arthritis, rash and vasculitis are common, and a variety of autoantibodies can be detected in the blood. In addition to fever, arthritis, rash, vasculitis and other manifestations, it can be accompanied by multi-system damage, and some of them are severe and can lead to death. In terms of treatment, most of the treatment is based on medication, glucocorticoids, immunosuppressants, etc. are more commonly used, and traditional Chinese medicine also has certain efficacy. In conclusion, connective tissue disease is a type of chronic disease with a wide range of symptoms and complexities, which is easily missed and misdiagnosed clinically. If there are signs and symptoms suspected of connective tissue disease, and it is difficult to explain by conventional diseases, you should promptly go to the rheumatology department for consultation.