Energy and environment form a nexus in which residents are the owners of tourism energy resources. Only a few studies have focused on the energy literacy of residents in ethnic tourism destinations and its impact on sustainable tourism. Using a qualitative research approach through field works and in-depth interviews in the Ping’an Village, Longji Terraces Scenic Area, this study explored the relationships between the energy literacy of residents and sustainable tourism in ethnic areas. The result showed that the energy literacy of the ethnic residents of Pingan village in terms of knowledge, attitude, and behavior has increased in line with the development of tourism, and both external and internal factors contribute to the improvement. Besides, the promotion of energy literacy among the residents not only has a positive impact on the tourists’ behavior but also brings about effective improvements in the local energy use structure and infrastructure, thus contributing to the sustainable development of tourism. This research extends the understanding of energy literacy from the perspective of ethnic residents and changes in energy literacy in remote ethnic villages under tourism development. The results also deepen our understanding of such changes in the behavior of tourists and tourism destination sustainability and enrich the empirical research to promote energy conservation and sustainable tourism development in ethnic areas.