With the rise and development of YanYue, some poems changed into Ci - poetics. This is the view of the editors of Si Ku Quan Shu. Ci - poetics germinated in the Tang Dynasty, and were in fashion in the Song Dy-nasy. After the Jin and Yuan Dynasties, Ci-poetics were gradually separated from music, and became a kind of prose. The theory about changeof Ci-poetics reveals the stage of development of Ci-poetics objectively, reflecting the general law about Ci-poetics'development in the Song Dynasty.