Study Evaluating the Efficacy and Safety of Triptergium Wilfordii and Acitretin in Psoriasis Vulgaris - CHINA201002016-2

Inclusion Criteria: * Adults of both sexes, between the age 18 and 75 years. * Have a diagnosis of psoriasis vulgaris,PASI score of 7 or greater. * Capable of giving informed consent and the consent must be obtained prior to any study related procedures. Exclusion Criteria: * Currently have erythrodermic,guttate or pustular psoriasis. * Have any active dermatoses which may affect disease assessment of psoriasis. * Have used any investigational drug,any biologic or any systemic immunosuppressants within the previous 1 month.. * Have used topical medications/treatments that could affect psoriasis or PASI evaluation (eg, corticosteroids, tar, phototherapy et al.) within 2 weeks. * Have any acute or chronic or recurrent infectious disease,which was difficult to control. * Have the history of HBV or HCV infection,or HIV antibody test positive. * AST, ALT or blood fat levels must be within 1.5 times the ULN range for the laboratory conducting the test. * Are pregnant, nursing, or planning pregnancy in the coming two years(both men and women) while enrolled in the study. * Have any severe systemic disease or have a history of malignancy. * Have shown a previous hypersensitivity to Triptergium wilfordii or Acitretin. * Have any other condition not suitable to join in trial,which are judged by investigator.