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 capable of reducing abnormal increase of triglycerides and total cholesterol in blood induced by diabetes mellitus and high fat diet, reducing liver enzyme level, reducing liver injury and fibrosis stage, and preventing or treating non-alcoholic fatty liver diseases (NAFLDs), hyperlipemia and arteriosclerosis.
