Abstract:Autoimmune thyroid disease (AITD) is the most common organ-specific autoimmune disease, which is often coexisted with other autoimmune diseases, including systemic autoimmune disease, such as systemic lupus erythematosus, rheumatoid arthritis, and Sj?grens syndrome, and organ-specific autoimmune diseases, such as type 1 diabetes mellitus. AITD and these diseases have common genetic background and inducing factors, similar immune mechanism and histological characteristics. When AITD coexists with other autoimmune diseases, the severity, activity and prognosis of the disease change. There may be a causal relationship between them, which needs to be confirmed by more in-depth research.