Abstract: OBJECTIVE To provide foundation for traditional Chinese medicine in treating psoriasis via studying the intervention effect of Qinzhu Liangxue Decoction on Th17 cells， STAT3 and RORγt of psoriasis patients. METHODS 60 cases of psoriasis vulgaris(of blood-heat syndrome) were selected for clinical research and randomly divided into treatment group(30 cases) and control group(30 cases)， with the normal group being 10 cases. Patients in the treatment group and control group was prescribed with oral Qinzhu Liangxue Decoction and acitretin respectively， with the treatment lasting for 1 month. Clinical efficacy was observed based on psoriasis area and severity index(PASI). ELISA was adopted to detect， compare and analyze changes of Th17 cells. Expression rules of STAT3 and RORγt in the lesion tissue of psoriasis were detected by immunohistochemistry technology. RESULTS PASI scores of both groups after treatment were lower than those before treatment， and the difference was statistically significant(P<0.05). Serum Th17 cytokines(IL17， IL23) of the two groups before treatment were higher than the normal group(P<0.05)， and both IL17 and IL23 of these two groups went down after treatment(P<0.05). Before treatment， the expression of STAT3 and RORγt via immunohistochemical detection in the lesion area of both groups was higher than that of normal group(P<0.05)， while it became lower after treatment(P<0.05). CONCULSION Qinzhu Liangxue Decoction plays an effective role in treating psoriasis by improving Th17 cells and regulating transcription factors STAT3 and RORγt.