This study is a single case study to investigate how art therapy using fairy tales affects vocabulary and behavioral changes in adolescents with developmental disabilities. The subjects were 15-year-old adolescents with Level 2 developmental disabilities who showed language characteristics of Asperger's Disabilities. This study conducted a total of 39 art treatments for 60 minutes once a week from January 2016 to December 2016 at the Institute of Language and Psychology, located in W City. In order to examine the changes in language development through art therapy, language problem solving ability test, receptive & expressive vocabulary test(REVT) were conducted. In the art therapy process, verbal and non-verbal communication and art activities in the language development area at each stage of art therapy were conducted. The expression and acceptance of the language and the behavior of the language were observed and the home-tree-person(HTP) test and landscape composition method(LMT) test were conducted as a supplementary picture test. In addition, three months later, the follow-up examination interviewed whether the subject's language and behavioral change continued through the guardian, activity assistant, and school help class special teacher. Summarizing the results of this study, first, assimilation art therapy has positively changed the vocabulary of adolescents with developmental disabilities, and this is a result of examining through language problem solving ability test and REVT. Second, active behavioral changes could be seen through the improvement of vocabulary through art therapy using fairy tales. The behavior of avoiding communication with others has been reduced, and the interest in people has increased in attachment to things.