Objective To study the mechanism of Taohong Siwu decoction on intrauterine adhesions (IUA). Methods The female SD rats were selected as the research object, and the IUA rat model was established by double injury of mechanical and infection, and randomly divided into IUA model group, Taohong Siwu decoction high (18g/kg), medium (9g/kg), low dose (4.5 g/kg) group and normal saline (equal volume normal saline) group, 10 rats in each group, and 10 rats were selected as normal group at the same time. After continuous gavage for 24 days, the uterine tissues of rats in each group were collected. The mRNA and protein expression of α-SMA, Col Ⅰ, FN, TNF-α, IL-6 and IL-18, and the protein expression of p-NF-κB and NF-κB, p-Smad2, Smad2, p-Smad, Smad3, p-Smad7 and Smad7 were detected by RT-qPCR, ELISA and Western blot. Results Compared with normal group, the expression of α-SMA, ColⅠ, FN, TNF-α, IL-6, IL-18, p-NF-κB, NF-κB TGF-β1, p-Smad2, Smad2, p-Smad3 and Smad3 in IUA model group were significantly increased, the expression of p-Smad7 and Smad7 was significantly reduced (P＜0.05). Compared with IUA model group, Taohong siwu decoction group could significantly reduce the expression of α-SMA, Col Ⅰ, FN, TNF-α,IL-6, IL-18, p-NF-κ, NF-κB, TGF-β1, p-Smad2, Smad2, p-Smad3, Smad3 and raised the expression of p-Smad7and Smad7 (P＜0.05), and medium and high dose group were more effective(P＜0.05). Conclusion Taohong Siwu decoction could inhibit the activation of NF-κB/TGF-β1/Smad signaling pathway, thereby inhibiting fibrosis and inflammation of uterine tissue in IUA rats.