This poem first describes the frontier fortress battlefield scenery with distinctive features, and uses rhetorical devices such as metaphor and duality to describe a frontier fortress scenery map, showing its broad and sad characteristics. Then, the poet uses metonymy to express his feelings for horses and his desire to make contributions without being appreciated. By chanting, praising or lamenting the fate of horses, the whole poem expresses the genius, lofty aspirations, feelings and resentment of people with lofty ideals, and its expression method belongs to metaphor. However, this poem has unique significance in the use of metaphor.