The present invention provides an application for a glucagon-like-peptide-1 receptor (GLP-1R) and glucagon receptor (GCGR) dual agonist polypeptide. The polypeptide provides features such as high enzymolysis stability, high bioactivity, zero adverse reaction, and the like. The polypeptide can reduce an abnormal increase to total blood cholesterol and triglyceride levels induced by diabetes or fatty diets, reduce liver enzyme levels, and improve upon liver damage and fibrosis. The polypeptide can also be used to prevent or treat diseases such as non-alcoholic fatty liver disease, hyperlipidemia, atherosclerosis, and the like.
