ABSTRACTIn recent years there has been growing enthusiasm among researchers for the promotion of online learning communities designed to support professional learning in preservice teacher education. The primary purpose of this qualitative study is to explore the role of such an online community in supporting student teacher learning during the school placement in a Chinese Normal University, and hence to enrich the understanding of student teachers' learning experiences in an online ecology. The study's subjects included a cohort of 42 student teachers enrolled on a four-year preservice teacher education programme, along with two university supervisors at one of China's teacher-training universities. Primary data were collected from six weeks of online threaded discussions and from semi-structured group interviews. Supplementary data were taken from an end-of-school-placement evaluation and web-tracking logs. Data analysis has been informed and illuminated by the theoretical proposition of communities of practice. The findings of the study indicate that the online learning community is a valuable resource for supporting student teachers both personally and professionally. Findings suggest that online communication not only helps student teachers tackle immediate teaching concerns and technical problems, but, more importantly, provides them with opportunities to reflect collectively, to co-construct new teaching ideas, and to gain professional discourse competence through articulating and negotiating their evolving thoughts on teaching as a profession. In this regard, student teachers are found to be more comfortable with online self-disclosure of their personal and professional encounters and critiquing each other than they are with face-to-face communication. The research also shows that university supervisors experience mixed feelings about the fact that student teachers are more able to take ownership of their learning and therefore become less dependent on supervisor guidance as time wears on. Furthermore, these findings provide evidence suggestive of a possibly reciprocal relationship between Chinese view of learning and the building of online learning communities.Based on the results of the study, I provide recommendations as to how the significance of the school placement can be reinforced in fostering distributed student teachers' professional growth. The results also contribute to a better understanding of the key factors in the design and implementation of effective online learning communities within preservice teacher education in China. Finally, the analytical approach used in this study provides fresh methodological insight into an alternative means of analysing online postings. It thus contributes both to the theorisation of learning communities in the context of computer-mediated communication, and to the further development of concepts drawn from the communities of practice literature.