The purpose of this study is to evaluate the efficacy and safety of IBI112 in the treatment of participants with moderate to severe plaque-type psoriasis.

Inclusion Criteria:

1. Diagnosis of plaque-type psoriasis with or without psoriatic arthritis for at least 6 months prior to first administration of any study agent
2. Must be a candidate for phototherapy or systemic treatment for psoriasis (either new to treatment or having had previous treatment)

Exclusion Criteria:

1. History of or current signs or symptoms of severe, progressive, or uncontrolled renal, hepatic, hematological, gastrointestinal, endocrine, pulmonary, cardiac, neurologic, cerebral, or psychiatric disease
2. Participant has history of erythrodermic psoriasis, generalized or localized pustular psoriasis, medication-induced or medication-exacerbated psoriasis, or new onset guttate psoriasis
3. Has received any therapeutic agent directly targeted to IL-17within 6 months of the first administration of study agent
4. Has received any therapeutic agent directly targeted toTNF-a within 3 months of the first administration of study agent
5. Has received any conventional therapeutic agent within 1 months of the first administration of study agent
6. Has received any topic therapeutic agent within 2 weeks of the first administration of study agent