The purpose of this study was to investigate the effects of art therapy on the foster child with oppositional defiant problem. This art therapy was aimed at expressing needs and anger as well as exercising role play after identifying foster child's oppositional defiant problem with foster mother's interview and pre-test results. Art therapy had total of 20 sessions and these process have helped to examine changes in problem behavior and picture test. The results are as follow. First, art therapy had positive effect on behavioral change with the consequence that K-CECL were changed in a positive direction. Second, art therapy had positive effect on psychological adjustment with the consequence that it could be assumed defiant attitude and aggression's reduction from KFD, HTP test. Finally, the implications and limitations were discussed.