This is a randomized, double blind, placebo parallel-controlled, multi-center clinical trial. Patients with psoriasis vulgaris were randomly divided into the experiment group （treated with TGP combined with acitretin capsules) and control group （treated with placebo combined with acitretin capsules）.The treatment lasted 12 weeks. The efficacy and safety were evaluated at the baseline, as well as 2, 4, 8 and 12 weeks after the beginning of treatment.The investigator's hypothesis TGP combined with Acitretin Capsulesin is more safe and effective than Acitretin Capsulesin to treat Psoriasis Vulgaris.