The present invention provides a composition comprising a GLP-1 receptor agonist and a glucagon receptor agonist and an application of the composition. More specifically, the present invention provides a pharmaceutical composition comprising a pharmaceutically effective amount of the GLP-1 receptor agonist and the glucagon receptor agonist, wherein the GLP-1 receptor agonist and the glucagon receptor agonist independently form a conjugate with a hydrophilic polymer, or the GLP-1 receptor agonist and the glucagon receptor agonist jointly form a conjugate with the hydrophilic polymer.