Traditional Chinese medicine has demonstrated its strength in treating psoriasis, which is characterized by a variety of methods of treatment, flexible use of drugs, high efficacy, low recurrence, and few side-effects. Experimental studies on the mechanism governing the TCM treatment of psoriasis have been conducted at the cellular level and the molecular level. The studies on proliferation and differentiation of keratinocytes and the inhibitory effect against them, apoptosis, intercellular adhesion molecules, cytokine, and haemorheology indicate that the laboratory studies on the treatment of psoriasis have now entered a very high stage since the eighties. The studies on relationship between typing of psoriasis based on TCM differentiation of symptoms and signs and changes in some laboratory indexes have been carried out by some researchers to explore the inherent pathological changes in typing of psoriasis based on TCM differentiation of symptoms and signs and to provide scientific basis for the differentiation and typing under a unified standard. However, the present studies lack depth and scope in the methods. In future, the laboratory studies should be enhanced to go further into the principles governing the TCM treatment of psoriasis and to seek new drugs that will be even more effective for psoriasis and can bring its relapse under control.