The theory of Feng Ya Zheng Bian (风雅正变）as one of the basic problems in The Book of Songs learning history. Firstly, The Great Foreword of The Book of Songs proposed the theory of Feng and Ya’s change. Then Zheng Xuan inherits this play and puts forward the concept of elegant decent, and puts the positive wind is elegant, the changing of Feng Ya and the corresponding world corresponding up, make elegant positive change has heen clearly defined standards, elegant hair Zheng is said will change into a system hy later scholars. Their theories that division of the Book of Songs make it has the systematic characteristic, the spirit more praise for varying wind more, deep resentment thorn work can play a better role in The Book of Songs political indoctrination. However, The Great Foreword of The Book of Songs and Zheng Xuan，8 theories has certain defects. The Great Foreword of The Book of Songs for the rise and fall times of the age division and the variable expression of praise and irony, which is easy to cause the misunderstanding; Zheng Xuan ’ s theory of the rise and fall of the age division is also easy to cause the later scholar ’ s clouhts and criticism.