This study explored the effects of sandplay therapy of the 5th grade boy in an elementary school according to the viewpoints of sandplay literatures and analytical psychology. He showed severe internal and external behavioral problems according to K-CBCL from his class teacher. The goal of the therapy was to lessen his severe behavioral problems under the free and protected space in the sandplay therapy. There were 42 sessions of sandplay therapy. The client showed his situations in the first parts of therapy(treasure, keeping precious things) by putting a treasure which was surrounded by keepers in the middle of the sandtray. In the middle sessions(blessing himself and holding the ceremony of magic squares), he repeated making birthday cakes in order to bless himself and holding the ceremony of magic squares with candles for transformation through numinosum. In the final parts(harmonization and obtaining the treasure), he showed harmonization with his situations and obtained the treasure he has sought for. This study shows the effectiveness of sandplay therapy since his severe behavioral problems were lessened.