Abstract: Under the influence of the decline of Confucianism and ritualism and the metaphysical theory of nonbeing, some hermit ideas such as "Xianyin " and "Chaoyin" appeared in the Wei and Jin Dynasties, which did not emphasize the fact but the meaning of seclusion, the focal point shift from "Yin" to "Yi". Scholars in the Wei and Jin Dynasties were intrinsically shaped by these new hermit ideas to pursue the way of freedom and carefree, and their spiritual character directly presented in the literary creation, which contributed to the elegance and beauty of the poetry remote from reality. After the repeated use of scholarly evaluation, "Yi" entered the field of literature and art, and became an important concept in the theory of books and essays. In this way, Yi gradually evolved from a daily phrase to describe the elegant manners of the scholars in Wei and Jin Dynasties to a poetic phrase to describe a certain style of poetry and literature, and developed into an important category of ancient Chinese poetics in later times.