This article not only theoretically explores the necessity and effect of constructive minilateralism and subregionalism in Northeast Asia, but also delves into a series of practical solutions from viewpoint of seeking common ground while reserving differences in this region. The main contents are as follows: First, the various obstacles that hinder the formation of regionalism, subregionalism and minilateralism in the Northeast Asia are discussed. That is to say, geopolitical realism, My Country First ideology, exclusive nationalism in the socio-historical context, and North Korea's latest provocations, etc. Second, this article explores the philosophy and basic principles of realizing Northeast Asia regionalism and minilateralism. Third, in the 21st century, Northeast Asia becomes the center of the world. It examines the core points, controversial focus and platform for building sub regionalism in the region. Finally, based on the institutional platform such as minilateralism and sub regionalism, the various ideas and practical plans of cross-border cooperation among major countries in Northeast Asia were discussed. Because there are a lot of obstacles, so first of all it is more appropriate to promote economic or functional minilateralism or sub regionalism than multilateral cooperation. In order to promote the formation of regionalism and minilateralism in Northeast Asia, the issues to be considered are as follows: First, for the sake of leading regional solidarity and minilateral economic cooperation, it is advisable for China, as a regional economic power, to implement a stable and responsible diplomacy. Secondly, regional solidarity based on credible politics and security should be promoted for a long time beyond the level of economic cooperation. Third, the primary prerequisite for the realization of Northeast Asian regionalism is that in the process of denuclearization of North Korea, the stability and peace mechanism of the Korean Peninsula should be established. Fourth, with the continued hegemonic competition between the United States and China in Northeast Asia, under the circumstance that countries in the region are pushed into so-called "East Asian Paradox", it is profoundly important for them to consider transition from the hostile relationship as the "Thucydides trap" to the order of "coexistence" in which competition and cooperation run side by side, and the two countries should explore a conversion plan for the foreign policy line. This mutual cooperation and peaceful coexistence of the US-China relationship will create a friendly atmosphere for the formation of regionalism in Northeast Asia. In the future, the cooperation of minilateralism in Northeast Asia will break the existing conflict between the maritime forces and the continental forces in order to promote peace. And along with the philosophy that "peace is economy", recent policies of common prosperity as the framework, such as China's "Belt and Road Initiative", North Korea's "Special Zone and Development Zone Policy", Russia's "New Eastern Policy", Japan's participation in the Belt and Road Initiative and South Korea's The "Korean Peninsula New Economy Map" are organically linked and it should promote the so-called "networked regionalism".