The purpose of this study was to investigate the one year of Creative Music Therapy process for Melissa, a 12 year old African-American girl with Down syndrome. In addition to Down syndrome, Melissa showed learning disability, behavior disorders, and autistic tendencies, and she could not communicate verbally. Before she was referred to music therapy, although she was observed to enjoy music, her response to music was limited to displaying the habitual body movement and playing the fixed rhythmic pattern. This study focused on how Melissa got out of the limits, expressed her body, and explored the instruments more freely through mutual improvisational experiences between therapist and client. Also, this study examined how Melissa who has low intelligence understood the structure of music and expressed herself. On analyzing her musical responses, the importance of the use of various idioms and scales not belonging to her culture and the importance of the musical reflection were discussed.