Under the impact of globalization, East Asia nations have pursued regional integration to strengthen their economic capacities and negotiating chips. Success is not foreseeable due to their vulnerability in economy and difference in many aspects. It takes the leadership of major powers to help them integrate. The United States and the European Union are interested because they both intend to expand their economic territory. Under the circumstances, US-led Asia Pacific Economic Cooperation (APEC) and EU-led Asia Europe Meeting (ASEM) are established to compete with each other in the East Asia area. This paper compares APEC and ASEM in terms of their structures, functions and essence. It is found that ASEM has the potential to catch up with APEC in leading East Asia integration. The presence and competition of APEC and ASEM also have impacts on the strategic triangle among US, EU and East Asia.