In spite of the expanded mutual dependence and the remarkable economic growth, discussions on intra-regional economic integration have been at a standstill. However, a trend for economic integration of East Asia is accelerating with the ASEAN cooperating system. ASEAN has been promoting economic integration since the early 1990s. It realized ASEAN 10by increasing its membership through the additions of Vietnam, Myanmar, Laos and Cambodia(CLMV countries) to enlarge the effectiveness of economic integration. After China agreed to create an FTA with ASEAN at the 5th ASEAN＋3 Summit in 2001, Japan considered the possibility of losing leadership over East Asia economic integration, leading it to see general cooperation with ASEAN. As a result, Japan promptly agreed to the FTA with Singapore in 2002 and instituted a practical work detail for promoting FTA with each Southeast Asian Country, signing the Framework for Comprehensive Economic Partnership with ASEAN during the 7th ASEAN＋3 Summit in bali. Moreover, the Japanese government is set to hold an ASEAN summit in December 2003 and hold a japan-ASEAN summit as a plan for economic relations with ASEAN. Regionalism will be consistently accelerated and in the mid-and long-term, forming the three major economic blocs the EU, America and East Asia will be inevitable. To prepare for this outcome, it is necessary to pay attention to the enlargement and deepening of cooperation in East Asia and to prepare synthetic plans to deal rapidly with the trend of economic integration. The range of East Asia cooperation under ASEAN＋3 is increasing, providing new opportunities to East Asian countries. Therefore, an East Asian economic cooperation community under mutual dependence would be useful for the present. Through the ASEAN＋3 cooperation channels, an exchange of views on regional issues of external economics and formulating steps together would raise the negotiation power of East Asian countries on the international stage such as APEC and WTO. Consequently, Korea should strategically promote the plan toward East Asian economic integration in three steps: first contracting an FTA with Singapore and ASEAN in the region; second, organizing the economic cooperation community of Northeast Asia and third, contracting FTA in the scope of East Asia. Korea should also continue to promote persistent relations with APEC and the United States while encouraging harmony with intra-regional countries using the ASEAN＋3 system as a lever to hasten FTA agreements toward a direct and overall economic integration of East Asia.