Abstract： Under the guidance of Chinese medicine thinking of examining syndrome and exploring pathogenesis，it is found that the "blood heat" of psoriasis vulgaris of blood heat type is only the appearance， and there are different etiology and pathogenesis behind it. The two main syndromes are wind-heat and toxin accumulation invading the blood，and damp-heat in the liver meridian invading the blood. Therefore， the general principles are established， which are resolving toxin and soothing the liver and resolving constraint to treat the root， and clearing heat and cooling the blood to treat the symptom. Qiaogen Xijiao Dihuang Decoction can be applied to cool the blood，and Danzhi Xiaoyao Powder can be applied to soothe the liver and resolve constraint based on syndrome differentiation.