Abstract: Zhu Xi's theory of essays is an important part of his literary theory, which consists of several theoretical aspects: the writer's cultivation, the conception, the structure, the wording, the style and the relationship between view of literature & truth.As he is a Neo-Confucianist, his theory of essays is with a distinct Neo-Confucianism color, which is obviously different from that of other ancient writers.These mainly show in following aspects:1)he links the writer's self-cultivation with the theory of Mind, emphasizing that only by improving his self-cultivation can a writer creates plain and natural works; 2)He holds that the meaning in essays should be practical in daily use, and emphasizes that a writer must create plain and natural essays; 3)He combines rationality with essay writing, and holds that truth is the root and an essay is a branch or leaf, and essays based on rationality are bound to have excellent lyric tone.