The purpose of this study was to explore the life experience of an adolescent who had leukemia with relapse. Data was collected by being a participant observer, interviewing the subject and primary caregiver and the narrative was accurately recorded. This study was a phenomenological research; Giorgi's qualitative method was used to analyze collected data. After repeatedly reading the content, it would be organized, generalized and analyzed. There were three themes in these findings: loss of self, suffering without understanding, and transcendence of illness experience. The result will help nurses to understand female adolescents' illness experience; help female adolescents reorganize themselves and channel their illness experience to face their development crisis.