Abstract: Objective To study the characteristics of anastomotic scar formation after bilioenteric anastomosis in rats. Methods A total of 30 SD rats were randomly divided into 5 groups, including: normal group, 3 days group, 1 week group, 2 weeks group and 1 month group, with six rats in each group. The anastomotic diameter, results of Masson staining, TGF-β1 staining and TGF-β1 relative quantification of PCR were compared between each group at different time points after bilioenteric anastomosis. Results The operation was completed successfully. The anastomosis of rats after the operation narrowed gradually, and the anastomosis in 2 weeks group and 1 month group was significantly narrower than the 3 days group (3.8±0.4) cm, (3.3±0.2) cm vs (4.4±0.2) cm, P< 0.05. The results of Masson staining showed that the bile duct wall was almost completely scarring at 1 month after the operation. The TGF-β1 staining and PCR quantitative results showed that the scar of the anastomosis became more and more stable over time, and the gene expression of TGF-β1 gradually decreased to normal at 1 month after the operation. Conclusion The anastomosis in rats after bilioenteric anastomosis gradually develops to scar stenosis. Symptom of scarring is most obvious in 1 week after operation, and it becomes relatively stable at 1 month after operation. Blocking the trend of scarring will be helpful to alleviate the formation of anastomotic scar and reduce the incidence of anastomotic stricture in 1 month after operation.