The purpose of this case study is to evaluate the effectiveness of the integrative psychotherapy for children with developmental disorders using expressive arts and play. For the last two and a half years after analyzing 95 development disorder cases through integrative psychotherapy, this study reflects on the brighter side of the treatment of development disorder problems. The aim is to look for possible solutions through integrative psychotherapy to the problems of adaptation, resentment, anxiety and other developmental disorder related problems in children. Through physical activities using play and expressive art in Integrative Therapy, these children had opportunity to find a way to express themselves in various ways. Through dynamic support, the therapy helped them to develop emotional stability and the language of expression and sociability. Also, letting children get involved in play activities indirectly expressively themselves with representations and guiding the parents through consultation to make the parents understand the changes of the child's overall behavior. Analyzing the pre- and post- test results, it shows improvement from 83 to 89 in the Social Maturity Index and from 65 to 68 points in the Wechsler's Verbal Indices. Evidently, the K-CBCL test also shows a very positive result reducing the problems of internalization from 62 to 50 and externalization from 63 to 53.