The purpose of this study is to analyze the current state and issues of political and economic friction between South Korea, North Korea and Japan. Moon Jae-in, the president of Korea, has announced ‘Korean Peninsula of peace and prosperity’ the ‘New-Korea Peninsula system’ building policy development. Because of New cold war system in East Asia in the diplomatic conflict. New-Korea Peninsula system is focused on South Korea's new role in the new cold war system. In New-Korea Peninsula system, South Korea should take a neutral and rational stance between improving inter-Korean relations and cooperating South Korea and Japan relations. And finally, South Korea should have become independent moderator in order to pursue peace and co-prosperity in Northeast Asia.