Rheumatic diseases are classified more, different rheumatic diseases caused by the etiology and pathogenesis is not exactly the same. At present, rheumatic diseases are mainly considered to be related to genetic factors, environmental factors, endocrine factors, infection factors, immune response, but for the vast majority of rheumatic diseases, the cause is not completely clear. 1, genetic factors: in many connective tissue diseases, genetic factors play a more important role, such as rheumatoid, ankylosing spondylitis. These diseases have a certain genetic tendency, and often are not single gene inheritance, but part of the susceptible genes, called susceptibility genes inheritance, resulting in immune abnormalities in the body; 2, environmental factors: such as daily exposure to radiation, ultraviolet radiation, chemical reagents, etc., may be the environmental factors that trigger the disease. As these external factors activate the expression of susceptibility genes of certain diseases, they lead to the damage of the organism and thus cause the occurrence of diseases. For example, in patients with SLE, long-term UV irradiation can cause abnormal expression of certain genes in the body, leading to damage to the body and eventually the emergence of SLE; 3. Endocrine factors: When the level of hormones in the body changes, it may also cause rheumatic diseases. For example, dysregulation of estrogen and progesterone is related to the occurrence of many rheumatic diseases; 4. Infection factors: For example, the presence of bacterial infection, fungal infection, and mycoplasma and chlamydia infection can directly or indirectly stimulate or initiate immune responses, such as infectious reactive arthritis; 5. Immune reactions: Patients can often check for the appearance of antibodies in themselves when they are examined, causing different degrees of damage or destruction of various tissues and organs .