This study was a clinical test report that the effectiveness of it was proven by conducting filial play therapy program based children-centered play therapy to two pairs of young children and mother with young children having behavior problems and they having inappropriate mother-children relationship caused by mother's postpartum depression. Filial play therapy program was conducted by play therapist for 120-150minutes once a week for the period of 10 weeks, and the effectiveness was assessed by comparing home video-recorded materials and questionnaires answered by mothers that were recorded and answered before and after the program. First, as the result of the study, mother's interaction strategy toward the children turned positive, and interaction assessment points increased qualitatively together with interaction unit frequency through filial play therapy program. Second, mother-recognized child's behavior problems points decreased. This filial play therapy program is more effective in reducing child's behavior problems by focusing on inappropriate and distant interaction in initial stage of nurturing between the mother who is the primary nurturer and the child than by focusing in child's personal internal aspects.