This article explores how Taiwanese immigrants become Australians, and considers how communication perspectives enrich identity study. The main theoretical frames in this study combine Barth’s theory of “ethnic boundary” and Mead’s symbolic interactionism, drawing on the strength of each to offset the weakness of the other. By extending and modifying Mead’s theory, Hecht’s communication theory of identity not only makes further linkage between communication and identity, but also provides clear analysis and presentation for observing complex interaction behaviors. The results show studying cross-border identity from the perspective of symbolic interactionism necessitates discovering how “significant symbols”, the key communicative factor to link self with community in Mead’s theories, are generated within interaction process. Grasping the twofold characteristic of significant symbols -- sameness (generated from the interaction within an ethnic group) and difference (generated from the interaction between ethnic groups), completely describes the dual quality of identity -- identical and different. The relationship between communication and identity is not as Mead thought, that identity is the outcomes of communication, but as Hecht pointed out, that identity reflects communication that externalizes identity. Therefore, significant symbols not only internalize into self identification during interaction among members of a community, they also externalize during communication practices to construct identity.