Abstract:Black Swan tells the story of a senior ballerina Nina who bravely changed herself character in order to create perfect "black swan". In reality,Nina is pure, clever, but in the rehearsal process, she gradually found herself repressed wild, wicked. On the basis of psychoanalyst Freud "ego, ID and superego" theory of personality structure, pureness, cleverness, crazy and evil are Nina’s performances of the ego and the ID .In the process of demonstrating the black swan, Nina has finally transformed herself into a real perfect"black swan”through intense confrontation armong the ego, ID and superego. This paper attempts to analyze deeply the transformation of Nina’s character with Freud's psychoanalytic theory.