This is a multicenter, randomized, double-blind, positive drug parallel-group controlled clinical study in China to evaluate efficacy, safety, tolerability and immunogenicity of HLX03 and adalimumab (Humira) in subjects with moderate to severe plaque psoriasis. This study will recruit 216 subjects (18-75 years old, male and female) with moderate to severe plaque psoriasis. The 216 subjects will be randomly assigned per 1:1 ratio into the following two treatment groups (HLX03 OR Adalimumab). The study will be conducted in three periods, including the screening period, treatment period and follow-up period. For each participating subjects, the maximal length of the study will be 56 weeks (including up to four weeks of screening time).