Confucius said to his students Yan, whose courtesy name was Ziyou, Bu Shang, and Zixia, so he was also called "Youxia, a Weiren". "The Analects of Confucius·Xian": "Literature Ziyou, Zixia." "Book of the Later Han·Biography of Lang?" "Tongyou Xia's art is like Yan Min's benevolence." It is said that Zixia is the student of Confucius who has the most published works, while Ziyou has not found the circulation of his works. You Xia said together, which only means that they are both students valued by Confucius, and it also shows that they both have attainments in literature. However, the literature of the pre-Qin period was the study of writing in a broad sense, which was strictly different from the literature we call today. However, the "Preface to Poems" written by Zixia is already a relatively complete literary theory. You Xia is one of the seventy-two sages of Confucius. "Historical Records" says that he was forty-four years younger than Confucius, and it is estimated that he was born in the thirteenth year of King Jing of Zhou Dynasty. He received his inheritance from Confucius after he returned to Lu in self-defense. Shilu was slaughtered by Ju Fu. After Confucius died, he lived in Hexi and became a professor. Wei Wenhou once taught him. It is said that the Analects of Confucius was co-written by Zixia and Zhong Gong; Mao Shi was passed down from Zixia, and one volume of "Yi Zhuan" was also written by Zixia. Xu Fang of the Han Dynasty said: "Poetry, calligraphy, etiquette, and music originated from Confucius, and the invention of chapters and sentences began with Zixia." Liang Xiaotong compiled the "Selected Works" of the Southern and Northern Dynasties and selected it with the "Preface to Poems." This article explains the characteristics, content, classification, expression methods and social role of poetry, and is a summary of Pre-Qin Confucian poetic theory. Literary writers have always regarded this as an eternal failure to publish. Yan Yan, whose courtesy name is Ziyou, is included in the literature department together with Zixia. "Historical Records" says that he was "forty-five years younger than Confucius". Based on this calculation, he should have been born in the fourteenth year of King Jing of Zhou Dynasty. After Confucius returned to Lu in self-defense, Zi You studied there, and later served in Lu as the Wucheng Prime Minister. Some people regard him as one of the authors of "The Analects of Confucius".