This study examines the effect of a child-centered play therapy course for pre-service early childhood teacher-child interaction. The participants in this study were 31 early childhood education majors at a three-year college. The results show that a child-centered play therapy course is effective in improving a pre-service teacher's interaction behavior. The results show qualitatively that: First, in initiative, pre-service teachers give each child the opportunity to select toys or to play, but not variously with toys or games. Second, in orientation to play, pre-service teachers decrease extremely inappropriate involvement, but miss appropriate moments. They guide each child's reaction by tracking, but not extensively. Pre-service teachers do empathetic reflection, but unsatisfactorily. Third, in emotional bonding, pre-service teachers encourage and support each child, but not specifically. Finally, in pleasure, they show pleasure, but not by language and gesture.