This study examines the changing perceptions of peace on the Korean Peninsula based on the annual “Unification Attitudes Survey” conducted by the Seoul National University Institute for Peace and Unification, and explores ways to secure peace on the Korean Peninsula through cooperative governance by neighboring powers. According to the results, first, the perception of the need for unification is decreasing year by year, and the perception of homogeneity in the need for unification is also decreasing. In addition, negative perceptions of the possibility of reunification are also on the rise, and mutual understanding should be promoted through reunification education and civilian exchanges on the political and economic benefits of reunification and the universal value of peace. Second, North Korea is perceived as the most threatening country in terms of the closeness of its neighbors. They were mostly negative about the neighboring countries’ desire to reunify the Korean Peninsula, but they recognized the need for cooperation among the four powers in this regard. In particular, they recognized that “inter-Korean cooperation” is the most important for the reunification of the two Koreas. Therefore, although the division of the Korean Peninsula is international in nature, the two Koreas, the North and the South, play a pivotal role in reunification, and diplomacy to persuade neighboring powers is necessary. In particular, it is necessary to strengthen cooperative governance of neighboring powers, recognizing that peace on the Korean Peninsula will be completed by unification and that the cooperation of neighboring powers is urgently needed.