What is literature? This question has always been controversial. Some say that literature plays an important role in the country management. Others say that literature is just a useless game of word. The former theory of literature had a great influence on Japan. The preface of Ryounshu and Keikokushu are two good examples. Despite the fact that Japanese literature absorbed the characters of Chinese's, however, it developed its own features. The aim of this paper is to ascertain the literary theory between Fujiwarano-Kintou in the middle periods of the Heian era and Pai Ju-Yi in Middle-Tang dynasty. Furthermore, I want to clarify the meaning of literature from the aesthetic and artistic point of view.