This study was aimed to investigate the effect of art therapy for sibling interaction center on sibling depression and communication. The subjects were the elder sister of middle school grade 3 and the younger sister of elementary school grade 3, who were both suffering from depression and applied to art therapy of sibling interaction center with a total of 35 times of each 120 min once a week for 28 Dec 2012 to 10 Sept 2013. The scores of examination of pre-test, post-test and follow-up test of each assessment tool such as Children's Depression Inventory (CDI), Satir Test for Communication, Kinetic Family Drawing(KFD) and Family Systems Diagnostic Procedure, and the contents of total therapy session used for this study were analysed. As the results, firstly, the elder sister showed a 6 point reduction and the younger sister a 13 point reduction in the CDI scores through pre- and post- tests, meaning some reduced changes in depression. Secondly, the elder showed an 11 point rise and the younger a 12 point rise in the congruence of communication, indicating some changes in the communication type. The siblings showed some increasing changes in their verbal and nonverbal communication for Family Systems Diagnostic Procedure and also some increases in the number of interaction for behavior observation. Therefore, these results indicate that this art therapy of sibling interaction center played some effective roles in a reduction in depression and an improvement in communication for these siblings.