Objective：To study the influence of total salvianolic acid（TSA） on the renal interstitial fibrosis caused by unilateral ureteral obstruction (UUO) in rats. Methods: Forty healthy Sprague-Dawley rats were randomly divided into 4 groups：the UUO group, sham-operation group, angiotensin-converting enzyme inhibitor (ACEI)-treated group (positive control), and TSA-treated group. The rats in UUO group and sham-operation group received gastric gavage with normal saline for 8 days before operation; rats in ACEI-treated group and TSA-treated group received ACEI (6 mg/kg by daily gastric gavage for 8 days) and TSA (20 mg/kg by daily gastric gavage for 8 days), respectively. All rats were killed 7 days after operation and the expression of transforming growth factor-β1 (TGF-β1) was detected by immunohistochemical method. The dynamic histological changes of renal interstitial tissues were observed by H-E and Masson staining．Results: TGF-β1 expression in TSA-treated (1.38±0.26) and ACEI-treated (1.38±0.26) groups was significantly lower than that in UUO group(P<0.05). TSA obviously reduced TGF-β1 expression and collagen deposition in the renal interstitial tissues and improved the renal pathological changes in UUO rats. Conclusion: TSA can evidently inhibit UUO-induced renal interstitial fibrosis in rats, which might be related with the down regulation of TGF-β1 expression．