Objectives: This study aimed to explore factors influencing on the alcohol problem of a grown-up child, the therapeutic techniques for family therapy, and the change of family members after family therapy. Methods: The data was consisted of recording transcripts and note-taking of 11 session family therapy. The study used a constant comparative analysis, and Miles & Hubermann's matrix and network display as a analysis method. Results: The results of this study revealed dysfunctional communication pattern, parents' negative rearing attitude, parents' experiences form the family of origin, and dysfunctional communication pattern in the parents' family of origin as factors influencing on the alcohol problem of a grown-up child. The study found the formation of therapeutic alliance, confirmation of problems, relabeling, reflection of the repeated dysfunctional communication pattern, guidance of communication skills, sharing and comparing with similar cases, and therapist's self-disclosure, confirmation of change as therapeutic techniques of family therapist. Conclusions: The result of study showed that the family therapy enhanced family members' functional communication skills and decreased the use of grown-up child's drinking.