Emily Dickinson is one of the most outstanding and influential American poets of the 19th century. Her poem “I Heard a Fly Buzz -When I Died” is told from a perspective of narrator who is near her death. As a typical modernist poet, Dickinson’s poems have prominent modernist characteristics. Her poetry language deviates from the norm, not limited to the language norms, forming a unique foregrounding effect from different levels such as phonetic level (the repetition of diphthong, flow, nasal, and iambic tetrameter and iambic trimeter), graphological level (the frequent use of capital words and dashes), rhetorical level (enjambment, contrast, synesthesia, oxymoron), semantic level (lexical meaning transference) and grammatical level (juxtaposition and ellipsis). Exploring the stylistic characteristics of Dickinson’s poetry based on the theory of deviation from the functional stylistics is helpful to excavating the implicated theme meaning and unique aesthetic value of Dickinson’s poetry.