This study discusses about transformation in South Korea's foreign policy towards North Korea in the era of Moon Jae In. The purpose of this study is to analyze more deeply to understand the things that influence Moon Jae In when making South Korea's foreign policy towards North Korea more open. The foreign policy taken by President Moon Jae In is Sunshine Policy. Based on the research conducted, the authors find internal factors and external factors that influence Moon Jae In making foreign policy. Internal factors that influence Moon Jae In making its foreign policy are ideological factors. While external factors are the actions of North Korea who refused the missile test.