Adult children accompanying their parents on trips is a particular form of family tourism. During family travel, adult children assume two roles: as tourists, they pursue personal hedonic experiences, while as children, they also bear the responsibility of showing filial piety towards their parents. These two roles entail inherent contradictions. How this conflict influences the formation of family tourism values between adult children and their parents, and ultimately impacts adult children’s intention to accompany their parents on future trips (re-travel intention), requires further in-depth analysis. Based on the perspective of tourist-to-tourist interaction and role conflict theory, this study applied a “value–attitude–behavior” model to empirically analyze the relationship between the interactions of adult children and parents during the tourism and their re-travel intention. An empirical investigation was conducted with 566 adult children from Jiangsu, Zhejiang, and Shanghai. The result of the structural equation modeling (SEM) analysis indicates that both positive interactions and role conflict have significant impacts on the formation of family tourism values, and these impacts are moderated by self-efficacy. Furthermore, these two variables influence attitude through the values of filial piety and family connection, which, in turn, affect the re-travel intentions of adult children. This study confirmed that the higher the self-efficacy of adult children, the better effect the positive interaction has and the less impact the role conflict has, which ultimately affects adult children’s re-travel intention. At the theoretical level, this study reveals the process of the formation of “adult children–parents” family tourism values, and provides practical insights for family tourism marketing.