The acceptance of family planning of hill tribe families from 8-village in Royal project Area is proper and related unavoidably to economic, social, cultural and traditional context. That is custom for inheritance. The hill tribe social value related to their belief which has impact to family structure. The extended family of Hmong and Akha inherit by patrilineal in which prefers heir to heiress. The enlarged family is the wealthier status, better social status and empowering to the family’s leader. Moreover, they have their rights for having more wives until they inherit the heir in which affects to women’s role and social status in Hmong and Akha society depending on giving birth for their sons only. The more society changes, the more development and opportunity provide for Hmong and Akha women. It increases the acceptance of family planning for women. While the development affects to Karen and Lahu village, they undergo with lacking of environment and natural resources. Therefore, the more women get higher social status, the less they have the children which is the widespread for accepting the family planning.