国家利益是外交研究的重要内容。进入21世纪以来，中国在外交中越来越强调国家核心利益，国家核心利益越来越成为中国外交中的一个热词，中国国家领导人、外交部门发言人常常在各种场合强调捍卫国家核心利益。一般而言，在国际社会无政府状态下，弱小国家面对大国压力的情况下，常常会诉诸国家利益、国家主权、国家安全等概念来维护自己的基本权益; 对于世界主导国和崛起大国而言，它们的生存利益相较于弱小国家更有保障。近年来中国综合实力在全球化进程中快速上升，已经仅次于美国，跃居世界第二。在这种情况下，为什么中国反而更加强调维护自身最基本的核心利益？为此，本论文以冷战后的中国外交话语中的国家核心利益为题展开研究，试图解释中国外交变化的内在逻辑。由于国际关系主流理论的局限，既往研究无法给出区分核心利益与非核心利益的界定标准，也就无法解释中国外交的变化逻辑。本文将国内政治引入对中国国家核心利益的研究，提出如下理论命题：中国外交话语中的国家核心利益是由国际权力冲突和国内政治冲突共同决定的。（1）国际权力竞争：一个国家在国际权力竞争中处于优势的条件下，更倾向于淡化核心利益，强化共同利益（shared Interest）；反之，当该国在国际权力竞争中处于劣势的条件下，更倾向于强化核心利益，淡化共同利益。（2）国内政治竞争：一国政府在国内某一议题中面临强大的政治反对势力的条件下，更倾向于强化核心利益，淡化共同利益；反之，则不强调核心利益。只有当某一问题既在国际权力竞争中处于劣势，又在国内政治中面对高政治冲突时，这一问题才会被界定为国家核心利益。国家核心利益从根本上看是中国执政党的政治利益在对外关系中的逻辑延伸。通过对台湾问题、涉港问题、涉藏问题和经贸问题四个案例的比较研究，发现中国之所以在实力快速增长的情况下仍然强调国家核心利益，主要与中国国内政治制度的属性和中国国家利益的全球扩散相关。界定国家核心利益是由国际因素和国内因素共同作用的结果。相比之下，国内政治压力是界定国家核心利益的决定性因素，国际压力也发挥着十分重要影响作用。国内、国际因素的互动是界定国家核心利益的关键点。本文的研究，对国际关系主流理论是一个批判性、反思性的研究，在此基础上，以期能对国家利益理论有所发展，在实践中对理解中国特色大国外交有所助益。

National interest is a significant topic in diplomatic study. Since the 21st century, Chinese government has attached an ever greater importance to core national interest in international relations, making it a buzzword in China’s diplomatic discourse and practice. To safeguard core national interest is frequently referred to by China’s state leaders and Foreign Ministry spokesmen on various occasions. Generally speaking, when the international community is in an anarchic state and small powers are subject to pressures from big powers, such concepts as “national interest”, “national sovereignty” and “national security” are resorted to by small powers to defend their fundamental interests and rights while the interest of the world dominant states and emerging powers can be maintained more easily. In recent years China’s comprehensive national power has grown exponentially in the process of globalization, ranking second in the world only next to the United States. However, why does China put more emphasis on defending its fundamental core interest in such circumstance？To figure it out, the research is conducted in this thesis on China’s national core interest in foreign discourse after the Cold War, aiming to explain the internal logic rooted in China’s diplomatic policy changes. Limited to the mainstream international relations theories, past studies have not set the criterion to differentiate core interest from non-core interest, therefore cannot explain the logic in China’s foreign policy changes.In this thesis domestic politics is included in the study of China’s core national interest and the theoretical propositions are made as follows: China’s core national interest in China’s Diplomatic Discourse is co-determined by international power competition and domestic political competition.(1) international power competition: when a nation has a dominant position in international power competition, it’s more likely to emphasize shared interest over core interest; when a nation has an inferior position in international power struggle, it’s more likely to emphasize core interest over shared interest. (2) Domestic political competition: when a government is confronted with strong domestic oppositions in a certain issue, it’s likely to reinforce core national interest over shared interest; vice versa. Finally, a certain issue is defined as core national interest only when the government proposing it has an inferior position in international power competition and simultaneously faces fierce domestic political oppositions. In essence，China’s core national interest is the logic extension of the ruling party’s political interest in foreign relations.Through a comparative study of four cases over the issue of Taiwan, Hong Kong, Tibet and issues over economy and trade, the research shows that China’s increasing emphasis on core national interest despite of its mushrooming national power is related to the nature of China’s political institution as well as the proliferation of China’s national interest in the international political domain.The defining of core national interest is affected jointly by international factors and domestic factors.Specifically, domestic political pressure is the determining factor in defining core national interest while international political competition also plays an important role. The interaction between domestic and international factors is the key to have a comprehensive understanding of core national interest. Critically reflecting upon mainstream international relationship theories, the study in this thesis aims to push forward the development of national interest theories and contribute to a better understanding of the diplomatic policies with Chinese characteristics in practice.