The past five decades have witnessed a political tension between Taiwan and Mainland China in relation to many countries on a global scale both economically and diplomatically. While both of them still claim the legitimacy of each other's national sovereignty since 1949, little academic attempts have been made to unravel the intricacies of students' identity regarding the cross-strait issues. This inquiry aims to bridge this gap by exploring Taiwanese students' language and cultural identities after studying in Mainland China. Qualitative data were collected and analyzed through a phenomenology framework that identified the salient themes that emerged during this process. The results illustrated several recurrent features that have shifted the participants' identity "historically," "culturally," "linguistically" and "academically." The data also revealed the complicated yet essential trajectory for their language and cultural identities to be formed and reformed after studying in Mainland China for them to be more acculturated into the new society. This study details the dynamics of these students' newly negotiated and defined identity and how this progression has further reformulated their outlook that they did not anticipate before.