The etiology of ankylosing spondylitis is analyzed from the theory of Chinese medicine, this disease can be caused by the lack of innate endowment or disordered regulation after birth, room and board, panic, depression and anger, and post-disease disorders, which results in deficiency of kidney and liver, and loss of glory of the directing vein, and the wind, cold, dampness, and evils take advantage of the weakness to invade and penetrate into the bone marrow and the spine. Deficiency of kidney, liver, essence and blood, so that the tendon contracture and bone weakness and the evil stay, and gradually lead to phlegm and blood stasis and mutual agglutination and become. In short, this disease is mostly due to Yang deficiency of the body, kidney and liver Yin essence deficiency, the deficiency of the ducal vein as the internal cause, wind, cold and dampness as the external cause of cold and dampness bias, and each other as the cause and effect of this disease. The basic mechanism of this disease is the lack of endowment, physical weakness, liver and kidney essence and blood deficiency, deficiency of the kidney governor, wind, cold and dampness of the evil take advantage of the deficiency of the deep invasion of the kidney governor, tendon and vein disorders, bone damage, the nature of this deficiency for the standard, the kidney governor deficiency for this, wind, cold and dampness for the standard, cold and dampness of the evil deep invasion of the kidney governor, the governor disease, but also can be involved in a number of internal organs.