Abstract: Objective　To investigate the expression level of interleukin-8 (IL-8) in children with biliary atresia (BA) and its relationship with cholangitis after Kasai procedure, and to explore the upstream signaling pathway regulating IL-8. Methods　(1) A total of 33 children with BA (18 cases with cholangitis and 15 cases without cholangitis after Kasai procedure), 6 children with biliary dilatation and 36 healthy children were included in this study. Serum samples were collected from children with BA and healthy infants. The serum expression levels of IL-8 and epidermal growth factor (EGF) were determined by enzyme-linked immunosorbent assay (ELISA). The activation of extracellular signal-regulated kinase 1/2 (ERK1/2) was detected by immunohistochemical staining in liver tissue samples from 6 children with BA and 6 children with biliary dilatation. (2) Human normal hepatocytes L-02 were cultured in vitro, and treated with phosphate buffer (PBS) and 25, 50 and 100 μg/L EGF for 24 h. The level of IL-8 was detected by quantitative polymerase chain reaction (qPCR). Cell lines HIBEpic, L-02 and LX-2 were treated with PBS and 100 μg/L EGF for 24 h, and the levels of IL-8 were detected by qPCR. L-02 cells were treated with 100 μg/L EGF and/or 5 mmol/L ERK pathway inhibitor KO-947, and the activation of ERK1/2 and the expression level of IL-8 were detected. Results　(1) The serum level of IL-8 was significantly higher in the BA group than that in the normal control group (P＜0.01), and the serum level of IL-8 was significantly higher in the cholangitis group than that in the non-cholangitis group (P＜0.01). Serum EGF was positively correlated with IL-8 in the BA group (rs=0.422, P＜0.01). Immunohistochemical staining showed that p-ERK1/2 was highly expressed in liver tissues of BA group. (2) The IL-8 expression in L-02 cells increased in a concentration-dependent manner after PBS and 25, 50, 100 μg/L EGF intervention. There were no significant differences in the expression levels of IL-8 in HIBEpic and LX-2 cells after 100 μg/L EGF treatment (P＞0.05), but the expression of L-8 was increased in L-02 cells (P＜0.01). EGF at 100 μg/L also induced the expression of p-ERK1/2 in L-02 cells, and KO-947 could reverse the changes. Conclusion　The serum IL-8 expression is significantly increased in children with BA before surgery, which is closely related to the postoperative cholangitis of Kasai. EGF could promote the expression of IL-8 in hepatocytes through ERK1/2 signaling pathway.