Abstract: An analysis of the synonymous relations of the monosyllabic notional words in Guo Yu shows that there three styles of the synonymous relations.This paper discusses the functions of these styles.Through a study of the formative process of the relations,the the present author discovers that“non-linguistic system”and“linguistic system”are the main distinctive ways of forming the synonymous relation of the monosyllabic notional words in GuoYu.