As one genre of literature,poetry is the elite in both Chinese language and its culture. With its unique characteristics of metrical and form regulations and the beauty of its simplicity and conciseness,Chinese Tang poetry is one of the brightest pearls in the world literature treasury.Translating as a purposeful activity was originated from the functionalist approaches to translation.From the perspective of functional grammar,this thesis attempts to study two translation versions of Song You Ren written by Li Bai. More emphasis has been put on the similarities and differentiations of the textual analysis. Through the analysis and compari son between the two translation versions,it is found that functional grammar is not only helpful to have a deep understanding of the discourse,but will also throw some light upon the practice of translation. As one genre of literature, poetry is the elite in both Chinese language and its culture. With its unique characteristics of metrical and form regulations and the beauty of its simplicity and conciseness, Chinese Tang poetry is one of the brightest pearls in the world literature treasury .Translating as a purposeful activity was originated from the functionalist approaches to translation .From the perspective of functional grammar, this thesis attempts to study two translation versions of Song You Ren written by Li Bai. More emphasis has been put on the similarities and differentiations of the textual analysis. Through the analysis and compari son between the two translation versions, it is found that functional grammar is not just helpful to have a deep understanding of the discourse, but will also throw some light upon the practice of translation.