Abstract: Objective To investigate the effect of Tripterygium wilfordii on levels of IL-17, IL-23 and IL-10 associated with Thl7/Treg Cells in the peripheral blood of patients with psoriasis vulgaris, and analyze its therapeutic mechanism. Methods Forty one cases of psoriasis vulgaris in our hospital from December 2016 to June 2017 were orally administrated with Tripterygium wilfordii tablets (20 mg, 3 times a day, for 8 weeks). The efficacy of treatment was evaluated by using Psoriasis Area and Severity Index (PASI) scores. The serum levels of IL-17, IL-23 and IL-10 in normal controls and patients with PV before and after the treatment was tested by using ELISA. Results The serum levels of IL-17 and IL-23 in the patients were significantly higher than those in the normal controls (all P＜0.01), while the serum level of IL-10 was significantly lower in patients as compared with the normal control (P＜0.01). After the treatment with Tripterygium wilfordii, the serum levels of IL-17 and IL-23 were significantly decreased (all P＜0.01), while the serum level of IL-10 was significantly increased (P＜0.01). PASI scores were decreased significantly after the treatment. The PASI score in patient was positively correlated with serum levels of IL-17 and IL-23, and negatively correlated with the level of IL-10 (all P＜0.01). Conclusion Tripterygium wilfordii shows a remarkable curative effect on psoriasis vulgaris. Its regulation on the levels of cytokines related to Th17/Treg cells may be involved in the mechanisms of Tripterygium wilfordii action.