The purposes of this study are to develop the FAT 3-generation integration program and investigate the effect of this program on happiness and family relationship among three generations. The study was conducted with 54 participants, including 16 from the first generation, 17 from the second generation, and 21 from the third generation. All of the programs were composed of 8 sessions and conducted in July 2016. The results of this study showed that first, the participants experienced improved happiness which could be explaind by good communicaion and mutual empathy among the generations. Second, the participants were less likely to disconnect family relationships. Third, they were more likely to connect family relationships.