Objective To study the effect of moutan cortex extract on Th17 cells of systemic lupus erythematosus (SLE) patients, so as to provide reference for clinical practice.Methods A total of 168 SLE patients admitted to our hospital from March 2012 to August 2013 were selected as subjects, andrandomized into the observation group and control group.84 patients in observation group received moutan cortex extract treatment and 84 patients in control group received conventional medical treatment.The Th17 and Th1 cell percentage of two groups before and after treatment were compared, and the incidence of adverse reactions were observed.Results All the indicators before treatment showed no statistically significant differences between two groups.After treatment, the Th17 cell percentage of observation group decreased to (0.27 ±0.15)%, and the Th1 cell percentage increased to (2.53 ± 1.72)%, showing more significant changes than control group (P<0.05).The reduction of IL-6 level, SLEDAI score and ESR after treatment were more significant in observation group than in control group(P<0.05).The incidence of adverse reactions was lower in observation group than in control group ( P <0.05 ) .Conclusion Moutan cortex extract can effectively improve the condition of SLE through reducing the Th17 cell percentage and increasing Th1 cell percentage with less adverse reactions.