This study aimed to explore the knowledge and coping styles of Taiwanese adults who had siblings with schizophrenia. Descriptive qualitative study was the design for this study and a semi-structured interview was conducted with the content audio-taped. The data was analyzed using content analysis. A purposive sample of 12 adults who had a sibling with schizophrenia was recruited. Three stages of cognitive process were found: 1) vague, 2) dubious, and 3) gradually understanding. Two themes in the vague stage included, "doubts on unusual behaviors," and "searching for causes to facilitate coping with siblings' unusual behaviors". Two themes in the dubious stage were, "suspecting siblings to become ill," and, "being compelled to accept the reality of siblings who become psychotic", and two themes in the gradually understanding stage were, "understanding the characteristics of schizophrenia," and "the impact on siblings of performing a caring role". The result of this study may empower psychiatric nurses to better understand the cognitive process of healthy Taiwanese adults who have a sibling with schizophrenia and provide knowledge of the different stages of illness and mental support with coping styles.