The invention relates to uses of polypeptide compounds having dual target agonist effect on glucagon-like peptide-1 receptor (GLP-1R) and glucagon receptor (GCGR), characterized by high enzymolysis stability, high biological activity and no adverse reaction. The polypeptide compounds are able to significantly improve a degree of BDL-induced cholestasis hepatic fibrosis in rats, and have significant therapeutic effects on diseases such as biliary cirrhosis. The dual target agonist polypeptides are applicable to the prevention or treatment of biliary cirrhosis and related hepatic fibrosis diseases.