"Leaves of Grass" is also a major innovation in artistic form. Whitman broke with the long-standing conventions of American poetry and opposed formalist tendencies, creating what was later called "free verse" poetry. This kind of free style, which has been compared to "rolling waves", uses a large number of refrains, long sentences, parallel sentences and exaggerated image language, and has rich expressive power. This has also had an impact on my country's new poetry since the "May Fourth Movement". He also made extensive use of symbols, metaphors and other techniques.