Abstract: In the Western Han Dynasty, Yang Xiong first put forward “Li Ze ” fu theory in which “Li” refers to the beauty of the prose and the grandness and richness of the content. “Ze” is Yang Xiong's reflection on the “Li” tendency of fu in his later years due to the influence of Confucian classics. This theory has become the main standard of creation and criticism of fu. The Ancient and Modern Elegant fu, supplemented by Yuan Hongdao and Wang Sanyu, took “Li Ze” as the standard of fu’s selection. However, in the late Ming, due to the influence of literary thought trend Dynasty, Yuan Hongdao’s “Li Ze” fu theory was innovated on the basis of Yang Xiong’s, which not only expanded the scope of expression of fu, but also stipulated the language and text form of fu.Yuan Hongdao also introduced the concepts of truth, interest, and rhyme into “Li Ze” fu theory, with the imprint of his “intelligent nature”literature.

Key words: Yang Xiong, “Li Ze”theory, Yuan Hongdao, intelligent nature, The Ancient and Modern Elegant fu