The way of starting a song with a metaphor was derived from the summarization of techniques of expression in The Book of Songs .The article holds that the discussions on the idea of starting a song with a metaphor from the pre Qin days to the Tang Dynasty,had two threads running of the way of starting a song with a metaphor,until KONG Ying da in the Tang Dynasty,gathered together all good annotations there had been about it,but the thread under discussion was a superficial study only to provide some inspirations for the formation of the theory of the way of starting a song with a metaphor in Feng and Ya (two of the three sections of The Book of Songs ).The other thread was of expositions of the way of starting a song with a metaphor,made by men of letters and literary critics of past ages,who had got away from its original meanings,and this thread formed in the Tang Dynasty one of our most important literary statements,which todays researches are mainly concerned with.The three stages are as follows:the stage of the two Hans annotating its original meanings;the stage of transtion from its annotation to its literary exposition in the Wei and Jin through the Northern and Southern Dynasties;and the stage of the formal establishment of the literary theory of the way of starting a song with a metaphor.