The aim of the Northeast Asian community building is to create an environment for living together peacefully and for realizing prosperity through cooperation. Economically, a community will integrate regional economies and share great interests for common prosperity. Politically, a community will stabilize the region with trust and cooperation. In terms of security, a community will realize the lasting peace of the region. The three economies of China, Japan, and the ROK account for a vast majority of Northeast Asia’s regional economy. China and the ROK are two key players in the Northeast Asian community building. China-ROK cooperation will be helpful for China-Japan relations that now appear to be in a difficult situation. Northeast Asian economic cooperation has developed into a multi-layered structure both in institutional and non-institutional ways. In order to build the Northeast Asian community, those three countries must first improve and make three close bilateral relationships. However, Northeast Asian community building should not just include China, Japan, and the ROK. The DPRK, Mongolia, and also Russia should be engaged as early as possible. Northeast Asian community is a vision and also a dream that needs great efforts to be realized by both a good spirit and real actions. The aim of the Northeast Asian community building is to create an environment for living together peacefully and for prosperity prosperity cooperation. Economically, a community will integrate regional economies and share great interests for common prosperity. Politically, a community will stabilize the region with trust and cooperation. In terms of security, a community will realize the lasting peace of the region. The three economies of China, Japan, and the ROK account for a vast majority of Northeast Asia’s regional economy. China and the ROK are two key players in the Northeast Asian community building. China-ROK cooperation will be helpful for China-Japan relations that now appear to be in a difficult situation. Northeast Asian economic cooperation has developed into a multi-layered structure both in institutional and non-institutional ways. In order to build the Northeast Asian community, those three countries must first improve and make three close bilateral relationssh However, Northeast Asian community building should not just include China, Japan, and the ROK. The DPRK, Mongolia, and also Russia should be engaged as early as possible. Northeast Asian community is a vision and also a dream that needs great efforts to be realized by both a good spirit and real actions.