This thesis takes symonymly monosyllable and disyllable nouns in《汉语水平词汇与汉字等级大纲》(修订本)as objects, in reference to the former scholars’research on monosyllable and disyllable adjectives, verbs, and adverbs, etc.

The paper discusses the reduplicative forms, grammatical meanings and the syntactical functions of disyllabic nouns, the meanings and functions of the reduplication form are highlight.

The ancient documents available indicate that the words of old Chinese seem to be mainly labic, but some poems whiten in Zhou Qin period, for example, these in Shi Jing and Chu Ci, record a large number of mono-morphemic disyllables, which are called lian mian n by Chinese scholars.

Contrasting the original of Erya with the annotation by Guo Pu,they were found that many important reasons for the appearance of disyllable.

During the mediaeval times came forth plenty of new words with new meaning,especially those disyllabic words,among which some were newly coined words and some others were old words taking on new meanings.