Objective To explore the X-ray and MRI manifestations of hip joint lesion in ankylosing spondylitis patients and give useful reference for diagnosis,assess of disease activity and therapeutic response and prognosis.Methods The X-ray manifestation and MRI manifestation of 64 cases of patients with ankylosing spondylitis were analyzed.Results In X-ray analyzed acetabulum joint changes 42,hip joint hyperostosis 47,hip joint interval narrow 13,hip joint osteoporosis 11,MRI analyzed synovial inflammatory change 64,subcartilaginous bone marrow edema 48,joint cartilage lesion and joint surface saccular change 42,tendon and ligament of enthesopathy 24,joint space change 13.Conclusion In patients with ankylosing spondylitis,X-ray manifestation of hip-joint lesion commonly included leacetabulum joint changes,hip joint hyperostosis and hip joint space narrowing while MRI manifestation included inflammation of synovium,edema of subcartilaginous bone marrow,and tendon of enthesopathy which suggested high disease activity.To suspicious hip-joint lesion in patients with ankylosing spondylitis,magnetic resonance imaging should be taken for judgment of disease activity and determine of treatment plan.