OBJECTIVE To study the effects of Wenyang huazhuo tongluo formula conta ined serum on the expression and methylation of retinoic acid related nuclear orphan receptor （RORγt），and to explore the mechanism of its regulation of Th 17 cell proliferation in the treatment of scleroderma. METHODS Wistar rats were given 15，30，60 g/（kg·d）Wenyang huazhuo tongluo formula intragastrically to prepare different doses of drug-contained serum ，and peripheral blood of scleroderma patients were collected to sort Th 17 cells. Using blank serum as blank control ，methyltransferase inhibitor decitabine （DCA）as positive control ， Th17 cells were treated with different concentrations of drug-contained serum ，and then the proliferation of Th 17 cells was detected by CCK- 8；mRNA expressions of RORγt and IL-17 were detected by qRT-PCR ，and the protein expression of RORγt was detected by Western blot assay ；the protein expression of IL- 17 in the cell supernatant was detected by ELISA ，and the methylation level of RORγt gene promoter was detected by methylation-specific PCR. The transcriptional activity of RORγt gene promoter was detected by dual-luciferase assay. RESULTS Compared with blank control ，Wenyang huazhuo tongluo formula contained serum and DCA could inhibit the proliferation of Th 17 cells（P＜0.05），reduced the mRNA and protein expressions of RORγt and IL-17，enhanced the methylation level of RORγt gene promoter and attenuated ， the transcription activity of RORγt gene promoter. Except for mRNA expression of Th 17 and the methylation level of RORγt gene promoter in drug-contained serum low-dose group ，there were statistical significance in above indexes of other groups（P＜0.05）. CONCLUSIONS Wenyang huazhuo tongluo formula can promote the methylation lev el of RORγt gene，and inhibit the expression of RORγt and the secretion of IL-17，so as to inhibit the proliferation of Th 17 cells.