Dry syndrome is a chronic systemic autoimmune disease that mainly involves the exocrine glands. In addition to dry mouth and eyes due to salivary gland and lacrimal gland involvement, the clinical symptoms are multisystemic due to damage of extra-glandular organs. Elevated autoantibodies and immunoglobulins can be found in the serum of dry syndrome patients. The former refers to the dry syndrome without other connective tissue diseases, while the latter refers to the dry syndrome with other connective tissue diseases, such as rheumatoid arthritis and systemic lupus erythematosus. In recent years, some scholars have also proposed in the clinic that when dry syndrome coexists with another connective tissue disease, it should be regarded as overlapping syndrome more appropriately. The development of primary dry syndrome is related to various factors such as genetic background, environmental trigger and immune abnormality. Under the background of genetic susceptibility, viral infection and other factors stimulate the secretion of intrinsic immune cells and glandular epithelial cells, and various chemokines and cytokines lead to T and B lymphocyte infiltration and promote proliferation and differentiation, and activated NK cells, Th1 cells and Th17 cells promote inflammatory response. Activated Tfh cells promote the formation of germinal center-like structures and assist B cells to differentiate into plasma cells, and activated plasma cells produce multiple autoantibodies to form immune complexes. A chain of abnormal immune reactions eventually leads to damage of exocrine glands and extra-glandular organs. The most prominent manifestation of dry syndrome is that patients can feel obvious dry mouth and dry eyes, accompanied by multiple dental caries, and some patients may develop arthritis, skin rash and oral ulcers, which are symptoms that patients can feel themselves.