On February 1, the former UN Secretary-General Ban Ki-moon announced that he will not participate in the next presidential election in South Korea, causing much imbalance in the political scene in the country where the opposition originally had an upper hand, giving a huge impact on the ruling party and increases the uncertainty of the Korean presidential election. Although the general election pattern favors the opposition forces, the leading opposition presidential hopeful Moon Jae-in is now facing the assaults from different sides. The election' is unpredictable, but it is certain that the uncertainty of the political situation of South Korea will temporarily reduce its function and predictability in East Asia’s geopolitics.