The thesis investigated idealism, reproduction of idealism, and factors related to idealism reproduction in the Yunanese in northern Thailand and at Santi Khiri Village, Tambon Mae Salong Nok, Mae Fah Luang District of Chiang Rai Province. There were three types of idealism, namely power idealism, idealism in resource management and idealism in group formation, unity and Chinese-ness. These idealisms were related to belief in supernatural powers, belief in natural power of Feng Shui, and social values, e.g., gratitude, prosperity and Chinese-ness. Idealism reproduction was reflected through rituals and acculturation with both internal and external factors like family, community, support from Taiwan and state policy on cultural diversity.