The objective of this study is to evaluate the efficacy, safety, pharmacokinetics (PK) and immunogenicity of SHR-1139 injection in patients with moderate to severe plaque psoriasis.

Inclusion Criteria:

1. Male or female, age ≥ 18 years old at the time of signing the informed consent form (ICF).
2. Subjects voluntarily sign informed consent form (ICF) prior to the commencement of any procedures related to the study, are able to communicate smoothly with the investigator, understand and are willing to complete the study in strict compliance with the requirements of this clinical study protocol.
3. A fertile female subject or a male subject whose partner is a fertile woman who has not had a child, has a sperm/egg donation plan for 72 weeks from the date of signing the informed consent form to the last dose, and is voluntarily using highly effective contraception (including the partner).
4. Female subjects must have negative pregnancy test results during the screening period and before randomized administration, and must be non-lactating.

Exclusion Criteria:

1. There are other skin problems that researchers believe can interfere with the evaluation of psoriasis.
2. A history of moderate to severe congestive heart failure, cardiovascular and cerebrovascular events or severe bleeding events occurred in the 3 months before screening, and the investigator considered this subject to be unfit for clinical study.
3. Had an opportunistic infection within 6 months prior to screening.
4. Allergic to the ingredients or excipients of the study drug.
5. The investigator determined that there were conditions that affected the safety and efficacy evaluation of the study drug.