This book introduces surgical treatment of ankylosing spondylitis in details, aiming to help surgeons to make better planning and technique. In part 1, authors mainly introduce the osteotomy technique in AS and surgery planning. Moreover, the benefits in organ function brought by spinal correction are introduced in the same chapter. The hips are the most commonly effected diarthrodial joint in patients with AS, and the stiff hip causes poor life quality. In part 2, authors mainly introduce the skills of total hip arthroplasty (THA) in AS. For some patients both with kyphosis and hip involvement, how the authors make surgery planning. ln part 3, authors introduce their experiences and methods, including the advantages and disadvantages when do spinal correction first or THA first, and the principle of making spinal correction match with THA well.