The emergence of the formalist school and the approaches of familiarization, highlighting, and non-normativity led to the examination of the method that alienates the language of poetry and opposes the norm of language. Non-normativity, due to the escape from the rules governing the language that causes the development of poetry, is one of the most important topics of formalists. In a work titled “A Linguistic Approach to English Poetry,” Geoffrey Leach divided it into eight categories, including phonetic, literary, temporal, intellectual, stylistic, syntactic, written, and lexical. The poets of the 1930s, who were the first pioneers of the ancient praise period and gradually became familiar with formalism and the approach of familiarization and non-normativity, were better able to apply these new linguistic approaches in their poems and benefit from them in the artistic development and development of their poems. Avesta is among the contemporary poets who have benefited from most of Leach’s non-normativity classification in his works. The aim of this research is to analyze and dissect the types of non-normativity in the works of Mehrdad Avesta. This research is descriptive-analytical based on linguistic studies based on Leach's theory.Research findings indicate that Mehrdad Avesta has benefited the most from the non-normativeness of integration and reduction. Since the poetic language in Arash Kamangir's poetry is epic, most of the non-normativeness in that work is more striking.