A case study was conducted to examine positive effects of art therapy program on the maladaptive behaviors and interpersonal relationships of a child with RAD(Reactive Attachment Disorder). Data were collected at Taejeon Research Institute of Developmental disorder, from May 24 to September 30. The subject was a 5 year old boy who showed developmentally inadequate social relationships and apparent disorder in most situations. A total of 16 sessions of the art therapy program was implemented for a subject and each session lasted approximately 50 minutes. The findings of the study were as follows: First, the frequency of maladaptive behaviors of the child gradually decreased through the art therapy program, In the beginning of the program, he had difficulties in remaining the seat during the whole session, and was obsessively afraid of the dirtiness with showing inattention in doing art work. But as the program went by. he became voluntarily more attentive without therapist’s directive strong restraint and his obsession on cleanliness was also improved. Second. the subject also showed changes in the aspect of interpersonal relationship. At the beginning of this program. he avoided physical or eye contacts. But as the program progresses. he was able to do physical contacts such as hand shaking or hug with therapist In conclusion. the findings of the case study revealed the potential effects of art therapy programs on improving maladaptive behaviors and interpersonal relationships in children with RAD. There is a need for developing more active and various art therapy programs to meet children's psychological need.