<p>This study examines the digital transformation and sustainable development of intangible cultural heritage (ICH), using Yi wedding customs in China as a case study. Based on fieldwork in Meigu and Zhaojue counties, the study documents the Kezhi debate and wedding rituals and evaluates how 3D motion capture, virtual reality (VR), and digital archives can improve the accuracy, interactivity, and educational value of cultural documentation. It also addresses risks of cultural simplification and misrepresentation. The study proposes a Technology–Institution–Agency model that links digital innovation, institutional governance, and the active participation of cultural bearers. Aligned with the United Nations Sustainable Development Goals, the findings show that digital technologies can support the preservation of Yi wedding customs, strengthen cultural identity among Yi youth, improve cultural education outcomes, and attract external visitors. The study contributes to debates on cultural sustainability, digital innovation, and inclusive development by offering both theoretical insights and practical guidance.</p>