The nursing therapeutic model that focuses on minimizing psychotic symptoms, without psychology and social rehabilitation, will reduce patient engagement and independence. Whereas, milieu therapy provides a structured environment with involving patients in active milieu to re-establish patient for controlling their own life or recovery. The purpose of the study is to investigate fundamental values that controlled nurses’ environment in inpatient care delivery in acute wards. The study is action research with qualitative and explorative design. Dialogue-based learning was an important intervention in the study. The dialogues were held on nine meetings for discussing some issues regarding the principles of milieu therapy. After dialogues, participants were encouraged to apply some milieu therapy principles in the field to upgrade nursing practice. Data were collected by multi-step focus group interviews. The focus group interviews were held three times on the sidelines of dialogues. About eight nurses of each of two acute wards were recruited as respondents by purposive sampling. Data were analyzed by qualitative content analysis. The finding presents some values that important in mental health care delivery, including respect and empathy, mutual trust, safety, and comfort, autonomy and independence, equity and humanity, and openness and predictable. The values that were identified are important to use for upgrading the quality of nursing practice. The nurses are expected to use the values in developing therapeutic milieu with creating therapeutic environment that is secure, full support, predictable, committed.