During the Chinese Civil War, the Chinese Communist Party (CCP) and North Korea maintained a close cooperative relationship. During this period, North Korea provided military support to the CCP and became a rear base for the CCP as well. In return, the CCP assisted North Korea with urgently required necessities such as food. Furthermore, in 1949 and 1950 the CCP returned three ethnic Koreans divisions of the People’s Liberation Army (PLA) to North Korea, greatly strengthening North Korea’s military capabilities. The grounds for cooperation on both sides were not only ideological, but also emerged from practical necessity. Sometimes, national interests were prioritized over ideological solidarity. Before and after the establishment of the People’s Republic of China (PRC), in order to establish a stable environment for economic development and to alleviate security risks, China continued to oppose North Korea’s pending attack on South Korea. In conclusion, China’s basic attitude towards the Korean Peninsula was to prevent a conflict between its own realistic and ideological interests; this attitude became the basis for the policy of the “stabilization of the Korean peninsula” that China implemented following its reform and opening up in 1980.