We often hear people talk about low back pain in our daily lives, and even we all experience low back pain in our lifetime, but if you have regular morning back pain, you must be highly alert to the possibility of developing ankylosing spondylitis (AS). AS is a chronic inflammatory disease that mainly affects the spine and sacroiliac joints. If not treated in a timely manner, it often leads to stiff deformities of the spine, sacroiliac joints and hip joints, manifested as scoliosis, anterior and posterior convexity, and difficulty in moving the lower extremities, resulting in lifelong disability and a huge mental and economic burden on the patient, family and society. In view of this, early diagnosis and reasonable, timely and standardized treatment of this disease are particularly important. In the early stages of AS, the symptoms are insidious, and most patients present with a single knee joint swelling and pain in the lower extremity, or with a complaint of iritis, which is most likely to be misdiagnosed as other diseases. Is there any way to avoid misdiagnosis? The answer is yes. The most significant differentiator is “morning low back pain,” which is present in almost 100% of patients with ankylosing spondylitis and is characterized by early onset of low back stiffness and pain that appears insidiously and decreases with activity. If you have morning back pain, you should not take it lightly and go to a regular hospital to rule out AS to avoid missing the best time for treatment and regret for life.