Estrogens exert indispensable effects on female reproductive organs but also on other target tissues including immune system. Studies showed that estrogens could regulate humoral and cellular immune. The change of levels and functions of estrogens may induce some autoimmune diseases. Further and deeper investigations are needed to study the relationships between estrogens and regulations of immune system, mechanisms and autoimmune diseases. It will benefit us to know the mechanisms of some autoimmune diseases related to estrogens and explore some new treatment strategies.