Objective To discuss the effects of Liuwei Dihuang Decoction on expressions of TGF-β1 and complement regulatory protein CR1 of the renal on IgA nephropathy rats.Methods Forty SD rats were randomized into normal group, model group, tripterygium glycosides group and Liuwei Dihuang Decoction group after adaptive feeding for one week. Complex method was used to establish IgA nephropathy model. All administration groups were given relevant medicine for gavage for 4 weeks;urine routine, the number of urine erythrocyte and 24 h urine protein were detected;creatinine, urea nitrogen, total serum protein and serum alburin were detected from blood;the renal pathological changes were observed under light microscope by HE and Masson staining;the expressions of TGF-β1 and CR1 were detected by immunohistochemistry.Results Compared with model group,Liuwei Dihuang Decoction could significantly decrease the proteinuria and hematuria levels and renal fibrosis changes of IgA nephropathy model rats, reduce the expression of TGF-β1, and raise the expression of CR1 (P<0.05).Conclusion Liuwei Dihuang Decoction can delay the renal fibrosis in IgA nephropathy rats through reducing the degree of TGF-β1 and promoting the expression of CR1.