Given the aging of the global population, the experience of adult children preparing to care for their aging parents is increasingly valued. In this article, I not only examined the associations between Taiwanese adult children’s attachment relationships with parents and their experience of filial anxiety but also took a psychocultural perspective to explore the mediating role of filial piety, the most representative value in the Chinese family. I collected survey data from 1305 middle-aged Taiwanese adults over 40 years old whose father or mother was alive and over 65 years old. The results from the first model for both father–child and mother–child datasets showed that secure attachment relationships with parents had a significant positive association with adults’ parental-welfare-focused filial anxiety B (FAB) but a significant negative association with their caregiver-role-focused filial anxiety A (FAA). The results from the second analysis indicated that secure attachment relationships with parents, for both father–child and mother–child datasets, had a significant positive association with adults’ endorsement of reciprocal filial piety beliefs, which significantly related to higher levels of FAB but lower levels of FAA. For both the father–child and mother–child datasets, secure attachment relationships with parents also had a significant positive association with their endorsement of authoritarian filial piety beliefs. Subsequently, their endorsement of authoritarian filial piety belief significantly related to a higher level of FAB in only the mother–child dataset. In conclusion, these findings broaden the understanding of adult children’s experience of filial anxiety that could be related to their attachment relationship with parents and their endorsement of reciprocal and authoritarian filial piety.