This paper tries to trace back the idea of East Asia economic cooperation，ASEAN plus Three，ASEAN Plus Six，and to give a description of the path from ASEAN plus three to ASEAN plus six，in order to show the different features of multileveled mechanisms and their interactions. The thinking underlined is that ASEAN plus three to ASEAN plus six both are indispensable components of East Asian economic cooperation process，and their roles in this process are complementary to each other.