EU and ASEAN have established a leading example of ‘interregional cooperation’ while constructing a unique relationship through ASEM. Recently, the US and China have proposed new ideas for interregional cooperation such as the ‘One Belt One Road Initiative’, and ‘Indo-Pacific strategy’. Interregional cooperation, however, depending upon economic cooperation faces difficulties due to competition between the regional blocks and the crisis of liberal internationalism. In this context, We will discuss conditions and ideas for Northeast Asia and S. Korea to ensure interregional cooperation in politics and security beyond the economic field. And will it be possible to make a model on regional cooperation from Northeast Asia? Furthermore, what should be the direction? What should Northeast Asia and S. Korea do now to build an interregional cooperation initiative?