Abstract: This article is part of a research paper titled “Conveying the Naga Beliefs of the Tai Lue people in the upper Mekong basin Multicultural Society”, it aims to study evidence about the origin of the idea, the motto of the Naga of the Tai Lue people in the upper Mekong basin culture. The methodology of the study has been used to use qualitative research methods, by collecting data from documents and field research, engaging and non-engaging observation methods, unstructured interviews, and in-depth interviews. The study area is the Tai Lue community area in the Sibsongpanna Tai autonomous region of the People’s Republic of China, and Tai Lue in northern Thailand. The results of the objective study on the origin of the Naga beliefs of the Tai Lue people. It was found that the origin of the Naga beliefs is caused by a snake worship cult, formed from the terrain, the climate of tropical rainforests with poisonous animals, and the livelihoods of agricultural societies that rely on natural water to nurture life, it was incorporated into the Buddhist faith and formed a common belief in the Mekong sub-region.

Key words: Tai Lue, Sibsongpanna, Naga, Upper Mekong Basin, beliefs