This case study aimed to investigate the effect of sandtray therapy to promote self-esteem for foster care child. In order to do the therapy, 11 years old female child in OO elementary school in G city has been taken. A total of twelve 50-minute sessions have been offered once a week from September 5, 2010 to November 21, 2010. Measurements included a pre- and post-test of HTP and SCT to confirm the improvement of self-esteem. The whole sandtray therapy sessions had intentions to increase confidence in the relationship between therapist and client, to let a child release deep emotion and to improve her self-esteem. The child showed difficulties to express own emotion in the early stage of the therapy, but could express it naturally by setting confident relationship with the therapist from the middle stage. She expressed the confidence by using symbol of communication during the sandtray therapy. She also actively participated in the therapy from then on. Finally the therapist could observe a child’s positive changes of self-growth. Results of this study indicated that the sandtray therapy is effect to improve self-esteem of a child.