Abstract: To interpret and evaluate the poetry anthology Metamorphosis of Anne Sexton，the 20th century American poetess，we should study her poetic interpretations to the classic stories of the Brothers Grimm from the three levels ：Romantic and well?worn themes，by deformation，show the alienation of society identity of contemporary American women；Personality assimilation，caused by the universal values of materialism ；marriage，great irony in the poem，is regarded as the the selfish product and captivity to the subject of marriage. When writing Metamorphosis，Anne Sexton surpassed the poet's own experience，and caused the resonance of the readers on a broader level.

Key words: American poetess, Anne Sexton, Metamorphosis, alienation, assimilation