Ankylosing spondylitis (AS) is a chronic progressive inflammatory disease that primarily affects the sacroiliac joints, spinal synapses, paraspinal soft tissues, and peripheral joints, and may be associated with extra-articular manifestations. The etiology of AS is unknown, and epidemiological investigations have revealed that genetic and environmental factors play a role in the pathogenesis of the disease, and the main clues to the diagnosis of the disease are based on the patient’s symptoms, signs, extra-articular manifestations and family history. This helps physicians to identify in clinical diagnosis. In recent years, the New York criteria for AS, as revised in 1984, have been used more often: 1. lower back carbuncle lasting at least 3 months, with pain improving with activity but not relieved by rest; 2. limited movement of the lumbar spine in the anterior-posterior and lateral flexion directions; 3. thoracic expansion of the thorax less than normal for the same age and sex; 4. bilateral sacroiliac arthritis grade II-IV, or unilateral sacroiliac arthritis grade III-IV. The diagnosis of AS can be confirmed if the patient has 4 and any 1 of the additional 1 to 3 respectively.