The purpose of this study was to explore and describe the experience of Dan-Jeon breathing training and of Qi as a essential substance in forming human body. The sample consists of 7 participants who are Dan-Jeon Breathing training in a Training center, Pusan, Korea. They were asked open-ended questions in order for them to talk about their experiences. With permission of the subjects, the interviews were recorded and transcribed. The summarized results of this research are following. 1. The purpose of Dan-Jeon Breathing The interview data was organized by themes into 4 categories : hope for health recovery, a concern about Dan-Jeon Breathing, seeking meaning of life, change of lifestyle 2. The experience of Qi during Dan-Jeon Breathing training The interview data was organized by themes into 3 categories : an autonomic movement of body, spiritual experience, conviction of existence of Qi. 3. The change after Dan-Jeon Breathing training. The interview data was organized by themes into 7 categories : physical health promotion, emotional relaxation, promoting brain function, positive attitude about life, love to others, investigation for self, improvement on Qi feeling..