This research is a case study that examines the effects and process of Sandtray Therapy for a 15-year-old female adolescent with trauma. The adolescent who suffered from family violence and sexual assault of this research not only had difficulty getting along with friends but also getting used to the school because of her depression and low self-esteem. This study was administered from March 2012 to October 2012 once a week for 21 times in total. The exact mental state of the participant was checked according to a clinical psychologist's mental test and also the change of therapy process was analyzed by Kalff's Sandtray Therapy 3 steps as well as pre and post tests scores for index of depression and self-esteem. Consequently, the result of the research showed that Sandtray Therapy was helpful to reduce depression and improve self-esteem of the adolescent. In addition, the adolescent expressed and cured by themselves while displaying desire and conflict which were suppressed under long time unconsciousness during the therapy session.