This paper shows from a cognitive linguistic standpoint, how the properties of conceptual structure reflected in body language can be revealed through analysis of opposites in sign language. Commonalities and differences in sign language are also discussed through cultural comparison between the Korean and Chinese languages. The main content of this paper can be described as follows. Firstly, similarities in sign language and conceptual structure were confirmed through analysis of opposites, showing that sign language bases its functions on a conceptual system shared with vocal language. Secondly, it was found that iconicity, conceptual metaphor and conceptual metonymy exist in sign language, with iconicity and metaphor existing simultaneously, based on similarity, and metonymy playing a general role. Thirdly, it was hypothesized that opposites maintain their consistency due to their origin in a universal cognitive disposition of human beings. However, it was confirmed in this study that sign language does not adhere to this feature and might instead be related to the different physiology, mind patterns and socio-cultural background of Chinese and Korean users. Finally, results of contrastive analysis of Korean and Chinese sign language showed that cross-linguistic universality was more in evidence than individuality. In other words, the basic experience of space possesses the universality feature.