Language is often regarded as one of the characteristics of interaction-based observed race, and heritage language is no exception. Considering the bilingual cultural environment of the Chinese community in Australia, this research analyses the language-ethnic identity relationships of Chinese-Australian adolescents. Drawing on in-depth qualitative interviews and participant observations, it examines the role of Chinese as a heritage language in these adolescents' ethnic identity formation process from a multidimensional perspective. The paper demonstrates that Chinese as a heritage language acts simultaneously as a link, an indicator and a stress in the construction of the adolescents' identities in the dimensions of self-identification, observed ethnic identity and reflected ethnic identity. It also highlights that there can be disparities among different dimensions of ethnic identity and examines the complex factors behind this.