The Medieval poetry in Chinese character is based on the poetics of parallelism, poetics of reproducing verse principles, and the poetics of symbol. Among these poetics, the poetics of parallelism is the principle that a certain phoneme, phrase or image must be corresponded by another phonemes, phrases or images. So, a certain phoneme, phrase or image could be amplified by its pair. Of course at last that phoneme, phrase or image can keep equilibrium with the another part. From the point that a phoneme, phrase or image amplify itself, the poetics of parallelism can be referred to a kind of verse production principles. Parallelism is a poetics of producing a couplet verse at every element of the verse, like phonology, morphology, syntax, and image. There are 71 kinds of parallelisms. Excluding the same sort of the parallelisms, there are at least 57 kinds of mutually distinct parallelisms. From this fact we can know two things. The one is that through the medieval age the parallelism was paid serious attention to by the medieval literacy especially in the poetry in Chinese character. I could not find whether the Western literacy subdivide parallelism like the case of Eastern literacy. From this we can know that parallelism is the characteristic feature of the Eastern literature distinguished from the Western literature. As the civil service examination test the capacity of making beautiful poetry in Chinese character, making a couplet by the principle of a parallelism is very important. So parallelism was took a serious view. As almost all of the medieval literacy took a civil service examination he had to study how to make a couplet by the principle of the parallelism. Every parent or teacher want to know whether his student or child could make the couplet. So he present a phrase in a poem or a line of a poem, a verse or a stanza to his pupils or his children, the pupils or the children had to form a counterpart to mate. If the counterpart is beautiful or characteristic then they placed his hopes on his pupils. The other is that the parallelism is consisted at every the elements of the poetry in Chinese character. The first is the phonemic level, the second is the morphological level, the third is the syntagmatic level, and the fourth is the level of image. As parallelism constructed by the strata of the elements of the poetry in Chinese character, so a sort of conception could be presumed that everything that exist in this world must have its pair. So parallelism has a philosophical especially ontological base. They thought that everything in the world had its counterpart inevitably, and that when a thing met its counterpart then it could form the whole. So that the solitary one is not normal pair is normal. This is the medieval ontology in the Eastern. The poetics of parallelism is based on this ontology. So we could know that through the Medieval age in the Eastern, literature could not distinguished from the philosophy, and the literati is also the philosopher.