A Study to Evaluate the Efficacy and Safety of SHR0302 in Patients With Non-Radiographic Axial Spondyloarthritis

Inclusion Criteria: 1. Provide signed informed consent. 2. BMI ≥18 kg/m2. 3. Participant has the clinical diagnosis of nr-axSpA fulfilling the 2009 ASAS classification criteria for axSpA but not meeting the radiologic criterion of the modified New York criteria for AS and have objective signs of active inflammation on magnetic resonance imaging (MRI) or based on high sensitivity C-reactive protein (CRP). 4. Participant must have baseline disease activity as defined by having a Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score \>= 4 and a Patient's Assessment of Total Back Pain score \>= 4 based on a 0 - 10 Numeric Rating Scale (NRS) at the Screening and Baseline Visits. 5. Participant has had an inadequate response to at least two Nonsteroidal Anti-inflammatory Drugs (NSAIDs) over an at least 4-week period in total at maximum recommended or tolerated doses, or participant has an intolerance to or contraindication for NSAIDs as defined by the Investigator. 6. If subjects are taking permitted csDMARDs or low-dose corticosteroid orally at baseline, the stable doses should have lasted for more than 4 weeks already. Exclusion Criteria: 1. Pregnant women or refuse to receive contraception during the study. 2. Lab abnormality within 4 weeks of randomization as follows: WBC count \<3.0×10\^9/L；neutrophil count\<1.5×10\^9/L;hemoglobin level\<90.0 g/L ; platelet count \<100×10\^9/L; AST or ALT levels greater than the 1.5 times the upper limit of normal; HBsAg or HCV or HIV antibody positivity. 3. History of other autoimmune diseases ; history of cancer or infection including tuberculosis and hepatitis; history of important cardiovascular events or thrombotic diseases.