Objective To investigate the value of human leucocyte antigen B27 (HLA-B27) combined with MRI and CT in diagnosis of ankylosing spondylitis (AS) with hip joint lesions. Methods The data of HLA-B27 detection, CT and MRI of 47 patients diagnosed with AS and hip joint lesions in the hospital between September 2013 and September 2015 were retrospectively analyzed. The accuracy of HLA-B27, CT, MRI alone and combined diagnosis and imaging findings of CT and MRI were analyzed. Results Among all subjects, 41 cases of HLA-B27 were positive (87.23%); In 47 cases, there were a total of 84 hip joints involved. The accuracy rate of HLA-B27 combined with CT and MRI diagnosis (95.24%) was higher than that of CT (79.76%) and MRI (84.71%) (P<0.05). CT scan showed 42 hip joints with space stenosis, 22 hips with articular surface damage, 38 hips with surface or bone destruction under hip surface, 67 hips with acetabulum and femoral head marginal sclerosis, osteophyte formation, 31 hips with extruding femoral synovial adherent sites, 31 hips with articular cavity effusion and 11 hips with intraarticular granulation tissue hyperplasia. MRI examination showed 47 hips with joint space stenosis, 48 hips with bone marrow edema, showing T1 low signal and T2 high signal. After enhanced scan, they was moderate enhancement; 54 hip cartilages showed irregular thickening, distortion and thinning. 41 hip joint articular surfaces were damaged. 55 hip joint capsules significantly expanded, with liquid signal shadow, and enhanced scan showed joint capsule thickening. Conclusion The combined diagnosis of HLA-B27, CT and MRI can improve the diagnostic accuracy of AS with hip joint disease, and provide rich information for clinical diagnosis and treatment.