The economic cooperation programs that can contribute to achieving peace in Northeast Asia may consist of constructing infrastructures (SOC) such as roads, bridges, ports, or communications, as well as sharing energy sources. However, North Korea’s political and economic status is the major obstacle for economic cooperation in Northeast Asian, with cost-benefit problems are repelling private capital and preventing cooperation to progress harmoniously. Nevertheless, it is still useful to do a case study on the fact that China is actively investing in North Korea. China, North Korea’s largest trading partner and investor, has a huge economic influence on North Korea, and it is alarming that North Korea’s economic dependence on China can grow if China increases its investment in North Korea and strengthens the economic cooperation between the two countries. Therefore, the objective of this paper is to inquire into Northeast Asia’s economic cooperation, focusing on the investment policy of China, which occupies an important role as the North Korea’s largest trading partner.