The majority of Hmong resided in Yunnan Province, southern China. In the mid-19th century, they migrated southward due to political conflicts. Nowadays the Hmong has become a minority ethnic group living in the northern part of Thailand, Laos and Vietnam. The report presents ethnographical data of the Hmong in two villages, Ban Vanghau and Ban Phoukhaokhouay, in the Phoukhaokhouay Basin. The ethnic group migrated from various highland areas in Vientiane to the area after 1950. They have gradually changed their lifestyle from shifting cultivation to paddy rice cultivation. The change has affected their socio-economic system. It is advised that the state be aware of change factors in order to lay out development plans due to an impending construction project of a dam and an electrical power plant. The author provides his perspectives on how the government can manage and solve problems and matters affecting the community as well as plans for future development.