A Clinical Study of JS005 in Patients With Ankylosing Spondylitis

Inclusion Criteria:

1. Subjects voluntarily particpate in this clinical study and sign the informed consentform.
2. Male and female patients aged 18-75 years at the time of screening (both inclusive)
3. Meet the diagnosis of active Ankylosing Spondylitis(AS), have a record of radiologicalevidence consistent with the Modified New York Classification Criteria for ankylosingspondylitis as revised in 1984 4. Diagnosis of active AS (active AS is defined as:BASDAI >= 4, total back pain score >=4, and BASDAI second question spinal pain score >=4)

Exclusion Criteria:

1. Pregnant or lactating women.
2. Active diseases that may confound the evaluation of JS005: other autoimmuneinflammatory diseases (including but not limited to systemic lupus erythematosus,rheumatoid arthritis, sarcoidosis, vasculitis, etc.) or chronic pain other thanankylosing spondylitis (including but not limited to fibromyalgia, osteoarthritis,etc.).
3. Active inflammatory bowel disease within 6 months prior to randomization. 5. Recurrentanterior uveitis or acute anterior uveitis within the last 4 weeks prior to randomization.
4. History or evidence of active or latent tuberculosis (TB), defined as a positiveinterferon gamma release assay (IGRA) or purified protein derivative (PPD) at the time ofscreening. 7. Positive hepatitis B virus test result 8. Prior exposure to JS005 or anyother biologic that directly targets IL-17 or the IL-17 receptor.
5. use of >= 2 TNF-α inhibitors.