On the basis of a brief introduction of Robert Frost which is the most famous American poet in 20th century, this paper makes an analysis of his poem The Road Not Taken from the aspects of meaning,form and theme.Taking "two roads diverged in a yellow wood" as a metaphor, the poet describes the dilemma of people when they have to make a decision.In the poem the poet perfectly combines the traditional form with profound meaning to tell us a life philosophy.