Most Thai Song families are extended families but somewhat smaller then those in the old days. As regards number of spouses, it is found that all of them practice monogamy. As for the rules of descent, the patrilineal descent is still very important. As for the rule of post residence, most of them prefer patrilocal residence. Patriarchy is their most popular authority pattern. Most of them still follow their traditional rules of leaving their bequests, i.e. more bequests to their sons, and the eldest son or the one who takes care of their parents will be given the largest bequest. There is a change in marriage among the younger generations, i.e. those who study in Bangkok or work anywhere out side of the community will marry people living outside their community. Most of them choose spouses by themselves. A few of them have their spouses chosen by their parents. Belief in spirits is a factor influencing Thai Song families’ behaviour at the present time as well as in the past. As for the terms of kinship, it is found that the children prefer standard Thai rather than Thai Song language. As for the duties with in the family, it is found that the most important duty is taking care of the children and the elders and the other is specifying the social status and mentally warm up. As for sharing work, men still occupy a higher status. The senior members also have roles over the Thai Song families as regards taking care of the housekeeping and being the consultant in the traditions and rituals. The factor affecting a change of the family structure is material and technological advancement. It keeps the relationship between brothers, parents and children at a distance because they move away from the community. This leads to marriage across ethnicity, and religion and an opportunity to meet someone outside the community. The new generation would like to have higher education in order to get a good job and earn high income. As regards the wedding tradition, there is an assimilation with Thai traditions and Chinese traditions. As regards maintaining their identities, it is difficult to find anyone who can read or write the Thai Song language. Furthermore, only the elders dress in traditional Thai Song style whereas the new generation dress in traditional Thai Song style only for important traditional occasions. Moreover, the expectations about the new generation is decreased because the elders understand their situation and surroundings. As for religion, there is an integration between the beliefs in Buddhism, Brahminism and spirits. The educational system and marriage to Thai people cause more cultural assimilation among the Thai Song. The children speak and read Thai efficiently while they use less Thai Song language. Marriage to Thai people in Bangkok causes Thai culture to have more influence on Thai Song culture.