The purpose of this study was to verify the effects of a conflict resolution program on conflict resolution strategies and friendship quality of children. The subjects of this study were higher-grader students of elementary school. Out of the students, 18 were into the experimental group, while the rest were into the control-group. The experimental design was the pretest-posttest control group design, and the 50-minutes conflict resolution program was treated for the experimental group twice per week (a total of 11 sessions). The scale of conflict resolution strategies presented by Ha Ji Wean (2005) and the scale of friendship quality of children presented by Rhee Un Hai and Koh Yun Joo (1999) were used as the measurement tools in this study. In order to supply the limitations of quantitative data, the journals of group participation of each session and the participation reports after the completion of the program were qualitatively analyzed. The results of hypotheses verification were as follows; First, conflict resolution strategies conflict was significant difference in enhancement of the compromising-integrating strategy and the obliging strategy, and reduction of the dominating strategy. Second, friendship quality was significant difference in enhancement of the friendship positive function, and friendship satisfaction, and in reduction of the friendship negative aspect, The results of the study confirmed that the conflict resolution program affected both conflict resolution strategies and the friendship quality of children.