Bai Juyi clearly put forward the requirement that poetry should be easy to sing in music in the preface to New Yuefu. He clearly put forward: "the quality of his words is different, and those who want to see it are easy to distinguish;" His words are straightforward, and those who want to hear them are deeply warned; Its substance is nuclear and practical, so people who use it can send a message that its body is smooth and smooth, and it can be played in music and songs. Here, "quality and diameter", "straightness and tangent", "core and reality" and "smoothness and smoothness" respectively emphasize that the language should be simple and popular, the discussion should be straightforward and exposed, the writing should be absolutely false and pure, the form should be smooth and fluent, and it has the color of ballads. In other words, poetry must be authentic, easy to understand and easy to sing in order to be considered the ultimate.
The purpose of easy singing is to make up for current politics. In modern terms, it is to express the voice of the people at the bottom with poems that are loved by the broad masses of the people, so that the voice of the people below can be heard in the sky, thus achieving political harmony and social development. From the origin, Bai Juyi is indeed a great patriotic poet.