This study seeks to investigate the academic second language socialization in the Korean context. And to have a deep and concrete interpretation of second language socialization, I tried to interpret this phenomenon from the perspective of practice and engagement in the Practice Community. To do this, I conducted one large ethnographic case study with 5 Chinese graduate students for one year and record their practice and engagement in the academic community.For the first step of my research, I reviewed the previous works about language socialization study in the Korean context and the study on KFL learners’ experience from a qualitative approach. Through this work, I found out that, there are only 5 papers about learners’ language socialization process and a few research to take the KFL learners as a matured sociocultural human-being. And the method or approach took by those studies are not appropriately or trustworthy enough. So I raised four research questions to fulfill the goal of my study. Which is 1) What can be called as the “Academic Second Language Socialization” in the Korean context; 2) What could be seen as the important constituents in the learners’ academic socialization, and how they are affected by the personal or contextual ways?; 3) How does the academic second language socialization look like? How does the personal feature affect the academic second language socialization?; 4) What theoretical or pedagogical implications we cat get from learners’ academic second language socialization.Before doing the case study, I tried to construct one conceptual frame for my study. I first reviewed the theory about language socialization which was first raised by Shieffelin & Ochs and other scholars such as Cook, Miller, and Heath. By the efforts of many anthropologic linguists, we could have one vivid and more precise comprehension about language socialization, which is one dynamic progress and could be hugely changed by the context and the agent of a subject. From this perspective, I focused on the academic context and the adult second language learners. The academic context is one professional, conventional, and have a complex relationship between members. Meanwhile, adult L2 learners are more self-dependent, motivated, and subjective. So the academic second language socialization would be more dynamic, vivid, and complex progress than L1 socialization. To investigate academic second language socialization thoroughly and deeply, I constructed my conceptual frame for my study by combing the “Practice Community Theory”, “Critical Discourse Theory” and the “Perspective of culture and identity negotiation”. In this way, I can see the learners’ academic second language socialization as their practice and engagement in the academic community, with the existence of power relationships and unreasonable access to all kinds of discourse and resources.By the conceptual frame, I designed my ethnographic case study. I had 5 Chinese graduate students as my research participants. By collecting Interview material, weekly reports, short interviews, and other materials related to their academic participation, community engagement, language proficiency, social practice, and perspective to community and self. I could have one whole idea about their participation and practice in the academic community. I tried to interpret their experience by emic perspective and use auditors to make my interpretation trustworthy.As looking through their participation and practice in the academic community, we could see that second language socialization in the Korean context could be one open, dialogical, negotiated, and also frustrated progress. Also difficult and frustrated, the participants tried to draw the resources they hold to make their participation easier and fluently, which included the “L1 socialization experience”, “interaction with the academic community” and “identity negotiation”. With these efforts, their academic second language socialization involved with “academic community”, “imagined community”, “online community” as well as “social community”, and could be phased as 7 steps, which are anticipation, exploration & observation, attempt and frustration, adjudication, re-attempt and internalization, formation and sustenance, and last realization. And I also found their academic socialization could be personalized by the effect of “competence in the academic community” and “the imagined community”.At last, I raised pedagogical implications from the academic community perspective, the Korean education institution perspective and the personal practice perspective based on the result of this study.