Abstract: According to Liu Xie's point that "Bi is plain while Xing is veiled", the thesis argues that Xing of Poetry is usually veiled in the following three aspects, including expressing emotions with objective things, images for expression, more meanings than the words. Meanwhile, the thesis traces the root of Xing to witchcraft. The development of Xing had experienced a course from witchcraft rites in the primitive religious period to Xing in The Book of Songs, and finally to the aesthetic appreciation of Xing after the beauty consciousness in Wei and Jin dynasties.