The purpose of this study is to investigate the experiences of art therapy in optimism for a resident adolescent and what the experience means to the adolescent. For this purpose, the participant of the study includes a 19 year old adolescent in a shelter and the investigator applied the methodology of a qualitative case study. In the study, the adolescent participated in 20 sessions, 60-minute weekly session twice or third per week between March 14 to May 16, 2019, in ‘G’shelter. The result of this study is as follows: First, the participant experienced self-understanding through the artistic activities of restructuring her past experiences. Second, she acquired self-control through a positive self-perception found in her artistic works. Third, she experienced social supports through exploring the relationship in art therapy. Finally, she grew immersed in the activities profoundly through the natural pleasure of art and learned to converse with herself, thus increasing self-belief.