Purpose: This study was aimed at evaluating the effects of Music Therapy for the autistic children. Method: The subjects of this study consisted of 3 autistic children who were trained in an Attachment Promotion Therapy Program for 6 months. The Children were all males and 4years 9months, 3years 1 month, and 3years 8month each, and diagnosed with Autism by Child and Adolescent Psychiatrists. Data was collected by using video-taping methods(ADOS, Fagot`s Interactive Behavior Code), an interview and observational methods(SMS). Music Therapy intervention was done once a week for 6 months. Data was gathered by quantitative and qualitative analysis. Result: This study showed that the Autism Diagnostic Observation Scale and Social Maturity Quotient(SQ) much improved after the Music Therapy. After the Music Therapy, the Interactive Behavior Code: Gaze, Gesture for the communication, Verbal language, Laughing/Smile, and Normal play behaviors increased more than before the intervention. As the results show, the child`s behavior became more positively responsive, playful, and attentive to others. Conclusion: This study suggests that Music Therapy might be an effective intervention for autistic disorder children in order to decrease autistic symptoms and increase joint attention behavior.