First, poetry creation advocates "serving the time" and "serving things". The core of Bai Juyi's poetry theory emphasizes that creation is for something, not for art. He said in the Preface to New Yuefu: "In short, for the monarch, for the minister, for the people, for things, for things, not for writing." He has a profound understanding of the lyrical nature of poetry, saying that "those who touch people's hearts do not rely on feelings first, words, sounds and righteousness", but he emphasizes "righteousness" and has strong practical utility. In Jiu Shu Tong Yuan, he said that ... articles should be written in time, and songs and poems should be written in substance ",and put forward the viewpoints of" writing for the time "and" writing for the substance ",which obviously inherited the traditional Confucian poetic thought.
Second, emphasize that poetry should satirize reality. It is the core of Bai Juyi's poetry theory to closely combine poetry with real politics and people's life. Bai Juyi emphasized the "thorn" side of poetry, but did not advocate "beauty". He said: "If you want to get rid of human feelings, you should first ask for poetic irony." He advocated that satirical poems should be written in a radical and straightforward way, instead of the so-called "lyricism, ending with propriety and righteousness" proposed in Preface to Shi Mao, let alone "remonstrating the main text", but to expose abuses loudly and plead for the people. This view advocates that literary creation should interfere with reality and criticize the dark society, which strengthens the realistic tradition of China's classical poetry and has a great influence on later generations.
Third, the relationship between content and form of poetry. He emphasized the unity of content and form, advocated that form should serve content, and opposed the separation from content and serving form. Jiu Shu Tong Yuan said: "Poets: root feelings, Miao characters, Hua Sheng, true meaning." Taking the growth process of fruit trees as a metaphor, he vividly and systematically put forward the four elements of poetry. Emotion and righteousness are content, words and sounds are forms, and "true meaning" is the content and the most important.
4. In the Preface to New Yuefu, he clearly pointed out that the criteria for writing poetry are "to be precise in speech", "to be straightforward in speech", "to be realistic" and "to be fluent in style", that is, he emphasized that the language should be easy to understand, the arguments should be straightforward and clear, the writing style should be absolutely false and pure, and the form should be smooth and fluent. In other words, poetry must be authentic, easy to understand, and easy to sing, in order to achieve the ultimate.
Bai Juyi's poetic thought and creation, which emphasized popularity and realism, played an important role in the history of China's poetry. It emphasizes realism, popularity and satire, and advocates the theory of writing for the monarch and the people, which is a direct inheritance of Confucian traditional poetics theory and a further development of Du Fu's current affairs writing. However, the self-styled theory of Yi Poetry also has its drawbacks, mainly in overemphasizing the practical function of poetry, ignoring or even deliberately rejecting and denying the aesthetic entertainment function of poetry and denying the artistry of poetry. He asked for the method of "recording" in poetry creation, and denied that poetry should use artistic techniques of imagination and exaggeration. In this way, poetry can't be dry, and it lacks a complete artistic image. In artistic expression, ignoring art should be implicit, advocating "speaking directly and to the point" and "the first sentence is aimed at its purpose, and the text shows its will". Poetry must be straightforward and simple, which is precisely the shortcoming of his few poems, which has to be said to be related to his poetic theory.