The purpose of this study is to determine whether Bawei Shenqi Pill is effective in the treatment of active ankylosing spondylitis (AS).

Ankylosing spondylitis is a chronic inflammatory disease, which mainly invades sacroiliac joint, spinal osteoid process, paraspinal soft tissue and peripheral joints, and can be accompanied by extraarticular manifestations, in severe cases, spinal deformity and ankylosis can occur. The overall prevalence rate of ankylosing spondylitis in China is about 0.3%, the peak of which is 20 to 30 years old. although the prevalence rate is not high, the disability rate is high, and the patients with ankylosing spondylitis are mainly young people of childbearing age, which are in a critical period of work and study. If the disease can not be controlled smoothly, it will seriously affect its learning and work efficiency, image appearance and even the ability of daily life.

Bawei Shenqi Pill originates from Zhang Zhongjing's synopsis of the Golden Chamber, is the representative prescription of warming and tonifying kidney yang, and is also suitable for the pathogenesis of ankylosing spondylitis "deficiency of kidney yang". The purpose of this study was to observe the therapeutic effect of Bawei Shenqi Pill on ankylosing spondylitis of kidney-yang deficiency type through a randomized controlled clinical study. To clarify the effect of Bawei Shenqi Pill on disease activity, joint function, TCM syndrome integral and quality of life in patients with ankylosing spondylitis, and to provide basis for the treatment of ankylosing spondylitis with Bawei Shenqi Pill.

Inclusion Criteria:

• Compliance with New York standards revised in 1984
• Syndrome differentiation of traditional Chinese medicine for deficiency of kidney-yang
• 18 to 70 years of age, male and female
• Being able to understand or sign an informed consent form

Exclusion Criteria:

• Other spondyloarthropathy that does not meet the diagnostic criteria of ankylosing spondylitis, and TCM syndrome differentiation does not belong to kidney-yang deficiency type.
• Age is out of range
• Do not agree to participate in this topic or can not participate in the whole process
• Complicated with other rheumatic diseases or other seronegative spondyloarthropathy.
• Pregnant, lactating women and patients with serious visceral diseases, mental disorders and severe extraarticular manifestations, such as heart, lung, liver, kidney or hematopoietic system.
• Have had myocardial infarction or stroke, congestive heart failure and active digestive tract ulcer patients.
• Those who had received other research drugs three months before screening.
• Inability or unwillingness to provide informed consent or failure to comply with test requirements.
• The researchers believe that it is not suitable for the owners of the study.