The year of 2016 is a volatile year of the Korean peninsula. North Korea’s nuclear tests changed the South Korea’s political and social ecology，which becomes more prefer to tougher policy，strengthening the Korea-US alliance. South Korea’s President，Park Geun-hye significantly adjusted her foreign policy at the beginning of this year. However，due to its lack of leadership，the accumulation of domestic problems，dispatching THAAD caused domestic divisions，and the “Choi Soon-sil Gate” started a heavy storm in the domestic politics of South Korea. The political chaos has no signs of calming down in the foreseeable future. Even though，THAAD deployment and military cooperation with Japan is still in steady progress.