Abstract: Objective To observe the effect of traditional Chinese medicine for intervention of phlegm and blood stasis in regulating TGF-β1/Smad3 signaling and relieving nephropathy in diabetic rats. Methods SD rats were divided into blank group (NC), diabetic model group (MC group), intervention of phlegm and blood stasis (RPDBS) group, phlegm-removing (RP) group and blood-removing (DBS) group. Diabetic models were established in all the rats except for those in the blank group. After 4 weeks of feeding, the rats in RPDBS group, RP group and DBS group were given corresponding drug intervention for 8 weeks. HE staining was used to observe the changes in renal histopathology. Western blotting and real-time fluorescence quantitative PCR were used to detect the expression levels of transforming growth factor-β1 (TGF-β1) and Smad3. Results The structure and arrangement of the glomeruli and renal tubules improved significantly in the treatment groups in comparison with those in the MC group. The expression levels of TGF-β1, Smad3 and p-Smad3 were significantly downregulated at both the protein and mRNA levels in the treatment groups (P<0.05), and the down-regulation was more obvious in RPDBS group than in RP group and DBS group (P<0.05). Conclusion Intervention of phlegm and blood stasis may inhibit the activation of TGF-β1/Smad3 signaling pathway and delay diabetic nephropathy and fibrosis to protect the renal function in diabetic rats.