Ankylosing spondylitis (AS) is a chronic progressive disease that mainly affects the sacroiliac joints, spinal prominences, paraspinal soft tissues and peripheral joints, and may be accompanied by extra-articular manifestations and, in severe cases, spinal deformities and joint ankylosis. The prevalence of ankylosing spondylitis in China is as high as 0.26%, and about 90% of patients appear to be HLA-B27 positive. It occurs mainly in men aged 15-30 years, but can also develop in women, and is rare in first-time patients over 40 years of age. The most common symptom of AS is low back pain. The pain is obvious at night when resting and accompanied by morning stiffness, and some patients wake up with pain in the second half of the night. It is often mistaken for “lumbar disc herniation” or “lumbar muscle strain”, etc. 3. Most of them develop along the spine from the bottom to the top. In addition to low back pain, 24%-75% of AS patients develop peripheral arthropathy at the beginning or during the course of the disease. The knee, hip, ankle and shoulder joints are predominantly involved, with occasional involvement of the elbow and small joints of the hand and foot. The main manifestations are asymmetric, minority or monoarticular inflammation, joint swelling or joint effusion. Patients with AS may also present with extra-articular manifestations: 1/4 patients may develop ocular uveitis during the course of the disease, alternating unilaterally or bilaterally, which usually resolves spontaneously, recurs or leads to visual impairment. AS can also be complicated by IgA nephropathy and amyloidosis. AS is a disabling disease and early diagnosis and treatment can improve the prognosis. Therefore, if you have back pain, back discomfort with morning stiffness, occurring before the age of 40, or if the symptoms persist for more than 3 months but decrease or disappear after activity, you should promptly visit the rheumatology department of your local hospital.