To rule out ankylosing spondylitis, the following five aspects can be ruled out: 1, family history, if the paternal or maternal line in the family, i.e. father, mother, there is no blood relationship with the onset of ankylosing spondylitis, can be temporarily ruled out. 2, inflammatory low back pain, that is, stiffness and pain in the back in the morning. If you have such symptoms, alternating hip and leg pain, stiffness in the back in the morning, improvement after activity, aggravation after sleeping or waking up in the middle of the night, if you do not have these symptoms, you can temporarily exclude. 3, check the human leukocyte antigen B27, also called HLA-B27, if it is negative, you can temporarily exclude. 4, do the sacroiliac joint MRI, if the sacroiliac joint MRI is not bone marrow edema, no joint effusion, you can temporarily exclude. 5.Blood test, if blood sedimentation, C-reactive protein, white blood cells, etc. are not elevated, it can be ruled out for the time being. If there are no positive signs and symptoms in any of the five areas, then ankylosing spondylitis can be ruled out completely.