The Tai Yoy culture relating to morals is passed down from their ancestors by the teaching of fathers and mothers. As for the culture relating to the law, it is practiced following the traditions. There is a supernatural belief such as the belief in spirits. Moreover, there is a belief in Kwan and a seniority system. When there are conflicts, the seniors are the arbitrators. As for the culture relating to the materials, the Tai Yoy build their houses by themselves with the help of their relatives and neighbours. The architecture of the houses is still traditional. They prefer to build their houses facing the streets. As for the culture relating to the relationship between the people in the society, the Tai Yoy is monogamous, they do not bother to have marriage certification because they think it is not important. The parents are responsible for raising and teaching their children. There are no prohibitions about the marriage. They can marry people in their groups or those out side the groups. There is an ancestor in each family to control the behavior of the people in their groups. As regards cultural assimilation, it is found that the country’s main culture has influenced the changes of the traditional culture following the assimilation theory such as the changes caused by the government’s policies in order to strengthen national security by providing education for local youth.