According to relevant statistics, 80% of male patients are found to have prostate and seminal vesiculitis, and it is believed that genitourinary infection is an important predisposing factor for this disease, and the infection spreads to sacroiliac joints and pelvis through the lymphatic system from the pathways of prostate, seminal vesiculitis, ulcerative colitis and restrictive enteritis, and then spreads into the somatic circulation to cause systematic symptoms and peripheral joints, tendons, and uveitis, and other lesions. In addition, trauma, thyroid disease, tuberculosis and localized infections are also predisposing factors for this disease. In conclusion, the disease is genetically based with the influence of environmental factors. Ankylosing spondylitis is a rheumatic disease with the highest rate of human histocompatibility antigen B27 (HLA-B27) positivity (95% positivity) and seronegativity, and the positivity rate of family members with HLA-B27 is also 30 times higher than that of normal controls, and about 60% of the members of the family can develop this disease. According to domestic and international reports, there is a tendency of familial development of this disease, and brothers have been found to develop ankylosing spondylitis successively. This suggests that genetic factors play a decisive role in the development of the disease, but the mode of inheritance is still unclear.