Compared with Southeast Asia and the European Union，the economic cooperation mechanism in the Northeast Asian region has fallen far behind. The new President of the United States Donald Trump took office in 2017 and announced his withdrawal from the TPP，which has caused an unpredictable blow to TPP member countries and predicted that the new framework for trade and investment liberalization in the Asia Pacific region will be redefined. This paper presents an overview of the FTAs in Northeast Asia，and predicts the future influence of South Korea’s related policies on Northeast Asian FTAs. At the same time，by using the equilibrium（CGE）model，the economic effects of FTA in Northeast Asia will be quantitatively demonstrated.