Abstract: Fu flourished after The Book of Songs and became entangled with it. It is often difficult for later generations to grasp its essence. WANG Qisun's theory of "other sons as ancestors" from the patriarchal system can best reveal the dynamic process of Fu's attachment to The Book of Songs. This theory links the role and position of Xunzi, Quyuan and Songyu in the evolution from The Book of Songs to Fu from the primary and secondary intimacy, points out the expansion characteristics of Fu after it is different from The Book of Songs as the "ancestor", and implies the fact that Fu scholars in the Han Dynasty attached to the study of The Book of Songs because of the pursuit of style dignity. The concept construction of The Book of Songs and the origin of Fu embodied by the Han people with Fu attached to The Book of Songs, as well as the requirement of "irony" and "eulogy" of Fu style similar to The Book of Songs in terms of functionality, which affected the transformation of the structure and style of the text of Fu in the two Han Dynasty, and echoed the characteristics of the language of The Book of Songs. This historical process of "respecting style" and "variation" of the attached sutra reveals the general concept of "attaching high to inferiority" in stylistics, reveals the internal requirements and development path of the new style when it was born, and is beneficial to the understanding of the generation of the new style later.