Autoantibodies are antibodies that are directed against one’s own tissues, organs, cells and cellular components. Normal human blood can have low titers of autoantibodies, but if the titer of autoantibodies exceeds a certain – level, it may cause damage to the body and induce disease. There are many autoantibodies in autoimmune diseases, the most important of which are antinuclear antibodies. The body’s growth, development and survival are maintained by an intact autoimmune tolerance mechanism, and the normal immune response has a protective defense, i.e., it does not react to its own tissues and components. Once the integrity of auto-tolerance is destroyed, the body sees its own tissues and components as “foreign bodies” and an auto-immune reaction occurs, producing auto-antibodies. However, if the titer of autoantibodies exceeds a certain level, it may cause damage to the body and induce disease. The detection of autoantibodies has the following clinical significance: 1, AID diagnosis and differential diagnosis, different AIDs have characteristic autoantibody profiles, disease marker antibodies or specific antibodies or disease-related autoantibodies are of great significance for AID diagnosis and differential diagnosis, and are essential for early diagnosis and timely treatment of AID. For example, anti-dsDNA antibodies, anti-Sm antibodies, anti-ribosomal P protein (rRNP) antibodies and anti-nucleosome antibodies in SLE. Certain autoantibodies are closely related to disease activity, and through the autoantibody potency and titer, the disease activity can be judged, treatment response can be observed, and clinical treatment can be guided. The common autoantibodies associated with clinical disease activity, such as anti-dsDNA antibodies in SLE, should be tested in the laboratory with emphasis on quantitative and regular testing. 3, AID disease regression and prognosis, certain autoantibodies are associated with disease development and regression. 4, AID pathogenesis research, through the autoantibody clinical application practice, can further study and elucidate the pathogenesis of AID.