This study is a phase 3 study,to evaluate the efficacy and safety of different doses of JAK1 inhibitor SHR0302 in subjects with active psoriatic arthritis.

Inclusion Criteria:

1. Provide signed informed consent；
2. Diagnosis of PsA fulfillment of the Classification Criteria for PsA (CASPAR) criteria with symptom onset at least 6 months prior to the Screening Visit；
3. Active arthritis at screening/baseline as indicated by >/= 3 tender/painful and 3 swollen joints；
4. Diagnosis of active plaque psoriasis or documented history of plaque psoriasis.

Exclusion Criteria:

1. History of other autoimmune diseases; history of cancer or infection including tuberculosis and hepatitis; history of important cardiovascular events or thrombotic diseases；
2. Non-plaque forms of psoriasis (with exception of nail psoriasis)；
3. Previous treatment with cytotoxic drugs; JAK inhibitor or bDMARDs within 6 months of randomization.