This thesis would attempt to cut in from heritage discourses of San-jia Poetry of Han Dynasties, investigate the formation of ”Register of Mao Poetry” by Zheng Xuan in East Han Dynasty, and also carry criticism on its gain and loss. For research outline of Zheng Xuan using ”Register of Mao Poetry” for three hundred pieces of works on ”Book of Songs,” its central idea is based on the theory of ”Fluctuation of Literary Pursuit” of Mao Poetry. As learned from the research of this thesis, the scale regarding the discourse of ”fluctuation of literary pursuit” is initially founded from the piece ”Grand Preface, Mao Poetry,” while its organizational structure is completed single-handedly by Zheng Xuan alone. Yet, such comment is not found with any trace in San-jia Poetry. In fact, it is with the help from Mao Poetry so that Zheng Xuan can have formulated the theoretical structure of ”Fluctuation of Literary Pursuit,” and because of it he had conglomerated the summation of ”Book of Songs” for two Han Dynasties and also substantively affect concept of poetry education for subsequent generations. As for the gain and loss of its theory, there are many discussion and arguments by later Confucian scholars, which can be used as basis of reference for my academic study on ”Book of Songs.”