The purposes of this study were to outline concepts and to explore developing model of training and accreditation of psychiatric mental health nurses .The action study research method was used, with a core group of research subjects recruited from the field of psychiatric mental health nursing education and clinical practice. The two-year process of discussion, clinical practice, reflection, and remodification, produced the following results. 1. Philosophy: A systematic, integrated ”light and salt” conceptual framework of nurses' development was established with humanity as its basis and excellence of quality as its benchmark, 2. The construct of the developmental model comprises (1) a preparation stage, (2) a formation stage, and (3) operation stage. These results might serve as a basis and a reference for sustained psychiatric mental health nursing.