Ankylosing spondylitis is defined as ankylosing spondylitis, and HLA-B27 negativity does not completely exclude ankylosing spondylitis, which needs to be determined based on specific clinical manifestations, ancillary tests, etc. HLA-B27 is associated with a variety of spinal and joint disorders. HLA-B27 is associated with a variety of spinal and joint diseases, and is a clinical indicator used to help determine whether a patient has ankylosing spondylitis. However, for a very small number of people, the test result is negative, so a negative HLA-B27 cannot exclude the diagnosis of ankylosing spondylitis. Patients with ankylosing spondylitis usually have limited lumbar flexion and lateral bending, with symptoms improving with activity but not with rest. To confirm the diagnosis of ankylosing spondylitis, in addition to the HLA-B27 test, tests such as blood sedimentation, CT and MRI are also required to further confirm and identify the degree of joint damage. If the patient is negative for HLA-B27 and has the above symptoms, he should go to the hospital in time and take active treatment under the doctor’s guidance, so as to avoid delaying the condition and causing adverse consequences.