Traditional Chinese medicines in the treatment of psoriasis based on the unique Chinese traditional Chinese Medicine signs

INTERVENTION: Group C:Control group (blood stasis syndrome) use placebo;Group E:Treatment group (blood stasis syndrome) use Huoxue;Group B:Treatment group (blood syndrome). Liangxuehuoxueta;Group D:Treatment group (blood dryness syndrome) use Yangxue Jiedu Tang;Group F:Control group (blood dryness syndrome) use placebo;Group A:Control group (blood dryness syndrome) use placebo; CONDITION: psoriasis vulgaris PRIMARY OUTCOME: psoriasis area and severity index (PASI); SECONDARY OUTCOME: The main indicators of TCM clinical symptom; INCLUSION CRITERIA: 1. be diagnosed as psoriasis vulgaris; 2. be diagnosed according to the unique TCM signs include "Xue Re" (blood heat), "Xue Zao" (blood dryness) and "Xue Yu" (blood stasis); 3. the lesional area<30% of body area; 4. 18 year to 65 year old; 5. Signed informed consent, voluntary subjects, and the informed process according to GCP requirements.