Abstract: Objective To study the clinical diagnosis and treatment of ankylosing spondylitis in 3 pilots and its aviation medical identification principles. Methods The diagnosis and treatment of ankylosing spondylitis in 3 pilots admitted to our hospital from 2009 to 2012 and its aviation medical identification were analyzed with its aviation medical identification principles put forward by reviewing its related literature. Results The 3 pilots were admitted to our hospital due to long-term repeated lower back pain for 8 months to 5 years. The pain was acute at night with "morning stiffness", which was relieved after movement. Laboratory test showed positive HLA-B27 and normal erythrocyte sedimentation rate and CRP. X-ray and sacroiliac joint CT revealed sacroiliac joint inflammation (gradeⅡin 1 pilot and gradeⅢin 2 pilots). The 3 pilots were diagnosed with ankylosing spondylitis according to the 1984 New York criteria. Their symptoms were significantly improved after they were treated with oral non-steroidal antiinflammatory drugs and sulfasalazine. The pilots were followed up for 6 months or 1 year during which X-ray showed no significant progress of the disease. One transport plane pilot was permanent grounded 6 months after the diagnosis of ankylosing spondylitis was established, 1 trainer fighter pilot returned to flight 1 year after the diagnosis of ankylosing spondylitis was established and 1 fighter pilot resumed flight 6 months after the diagnosis of ankylosing spondylitis was established. Conclusion It is very important to diagnose and treat early ankylosing spondylitis in pilots. Flight conclusion should be made according to the overall assessment of the disease, therapeutic effect, aircrafts species, flight duty, and will of individual pilot. Pilots who are specially permitted to fly should be closely followed up.