Purpose This study aims to explore the differentiated strategies of online identity construction among Mongolian, Tibetan and Uyghur users on the Weibo platform, and analyses the correlation mechanisms between specific cultural representations and social capital accumulation. Design/methodology/approach Through virtual ethnography, the authors developed a three-dimensional coding framework encompassing visual, enumerative and narrative dimensions to systematically analyze the personal profiles of 361 self-identified ethnic minority users, evaluating their cultural capital representation strategies and social capital conversion. Findings Different ethnic groups demonstrated unique identity expression pathways: Mongolians preferred symbolic rational presentations, Tibetans emphasized experiential narrative sharing, while Uyghurs tended towards implicit cultural expressions. Social capital accumulation was significantly correlated with contextualized image presentation, markers of multicultural consumption and embodied cultural practice expressions. Each ethnic group exhibited differentiated capital conversion logic: Mongolians emphasized practical demonstrations over abstract identification, Tibetans relied on cultural performance and community connections, while Uyghurs centred on regional practice linkages. The study also identified a “high disclosure-low return” dilemma, reflecting the existence of the third-level digital divide. Social implications The findings provide policy insights for constructing inclusive digital cultural spaces, highlighting the central role of information literacy education in digital inclusion strategies and offering empirical evidence for advancing the construction of the Chinese national community and a shared future in cyberspace. Originality/value This study reveals three major characteristics of ethnic minority cultural capital in digital environments: multimodal integration, strategic fluidity and practical priority, challenging the assumption that ethnic minorities necessarily reinforce visual ethnic markers. It extends the cultural capital theory to social media and cross-cultural contexts.