Abstract: Objective：To investigate the effect of IGF-1 on renal interstitial fibrosis in rats with unilatreal ureteral obstruction(UUO).Methods：Totally 30 rats were randomly divided into 3 groups, with 10 rats in each group, namely, sham group, model group and IGF-1 group. Renal interstitial fibrosis models were made by unilateral ureteral ligation. In the sham group, the abdomen was opened and then stitched; in the model group, physiological saline was intragastrically injected, 0.5 mL a day; in IGF-1 group, recombinant human IGF-1 was intragastrically injected, 750 mg/(kg·d). At the 14th day after the operation, the rats were anesthetized, and related materials were taken, the kidney function was tested, and   Col-Ⅲ，TGF-β1 and PAI-1 expressions in kidneys were observed.Results：The expression of BUN，Scr，Col-Ⅲ，TGF-β and PAI-1 in the model group were significantly higher than those in sham group, the difference having statistic significance. After the intervention of IGF-1, the level of BUN，Scr，Col-Ⅲ，TGF-β and PAI-1 in IGF-1 group was significantly higher than that in sham and model group, the difference had statistic significance（P＜0.05）.Conclusions：IGF-1 plays a role in the pathophysiological process of obstructive nephropathy，especially in the renal interstitial fibrosis.