The focus of this research is the relationship between economic cooperation and security regime in the East Asia based on the theory of neo-functionalism. After the Cold War, the economic cooperation in the East Asia become deeper, meanwhile, the North Korea's nuclear problem is still the hotspot in the East Asia. In the process of cooperation in the East Asia, the relationship between economic cooperation and security regime is complementary, which could solve the North Korea's nuclear problem. The process and frame of the relationship between economic cooperation and security regime in the East Asia, will be analyzed in this thesis for offering the government¡¦s decision-making about the possibility of Taiwan¡¦s engagement in the regional cooperation in East Asia.