传统世界里，以“权力”为导向的国际关系更多地关注军事上的胜利和经济上的强大。然而在当今的信息时代，政治也与赢得人心的“故事”有关。因而传统的政府间外交也正在被越来越多的非传统外交形式所“改写”。公共外交就是其中之一。 如今，面对很多前所未有的现象和问题，学术界对最基本的公共外交定义也尚未达成共识。对公共外交的研究既无从借鉴经验研究，也无法求助于主流的国际关系理论。因此，从解决公共外交遇到的实际问题出发，需要拓宽理论维度，尽可能凝练出其在理论上的归宿。 通过对现有文献的分析，本文在已有的公共外交研究中发现了两个彼此相关的研究不足。其一，对公共外交的经验研究远多于理论研究，因此缺乏一套清晰的公共外交指导原则；其二，对特定国家公共外交的理论研究难以复制到其他国家，因此需要跨国普遍适用的，可重复的公共外交原则。鉴于此，本文聚焦于公共外交的理论研究，并提出这样一个核心问题：是否存在普遍适用的可以指导公共外交实践的一般原理？ 致力于解决这个问题，本文旨在验证如下假设：如果哈贝马斯的交往行为理论可以用于为公共外交的理论化研究提供指导，那么有可能在此基础上凝练出一般性、跨国性的公共外交原则。 为此，本为选取了批判理论作为研究的分析框架。从法兰克福的社会批判理论，到国际关系批判理论，再到具有明显批判理论特征的交往行为理论。在分析了现有定义及其缺陷的基础上，作为论证的基石，本文将公共外交界定为“遵照交往理性范式，公共外交是由政府主导或资助，多种非国家行为体共同参与的，在数字媒体时代通过塑造和影响公众舆论，增进好感，旨在提高国家良好声誉和形象的一种双向实践活动。”特别地，本文从权力逻辑、运行方向和价值预设三个方面分析了软实力理论适用于公共外交理论化研究的内在悖论。 接下来，文章对交往行为理论用于公共外交研究的可行性进行了论证。充分说明了公共外交的实践环境中的确存在“交往行为”诞生的“理想的言语环境”、“生活世界”、“公共领域”三个条件，因而公共外交可被视作一种交往行为。以此搭建起交往行为理论与公共外交的联系。 此后，本文以交往行为理论为指导，重点研究了公共外交的本质属性、交往媒介、交往规则三个方面。 第一，正是因为公共外交的这种“交往”本质和体现出的交往行为特性，所以它必须是遵循交往理性和主体间性的实践行为。主体间性特征也就当之无愧地成为公共外交的基本属性。所谓主体间性，强调的是公共外交的各参与行为体之间享有同等重要的地位，这就与工具理性思维所体现出的“主体—客体”、“主体—对象”的关系截然不同。主体间性寓意公共外交是一种重视双向互动的交流。 第二，公共外交以公众舆论为基础，以“公共舆论场”为交往媒介。通过对哈贝马斯有关“公共领域”理论的思考，本文认为，“公共舆论场”的主体是公众舆论，它是“公共领域”中形成的与国家形象和外交政策有关的部分。公共舆论场表现出三个方面的特性：参与主体的公共性、运行制度的开放性、对公共权力的合法性批判。为了更好地突显出公众在公共外交中的主导作用，本文以跨国公司的危机公共外交为例，着重突出公众角色从被动接受者到成为利益攸关者的变化。 第三，话语是公共外交的交往载体。公共外交突出的特征不仅延续了传统外交的非武力方式，更是打破了不同“语言”之间的藩篱。作为一种交往行为，在公共外交实践中应该“怎么说话”，也即公共外交中的言语有效性问题，是交往行为理论对公共外交理论化研究的又一有益贡献。作为一种言语行为，公共外交中的话语需要同时满足三个有效性声称：真实性、正当性和真诚性。 此外，本文从公共外交对主体性互构的角度进一步分析了构成国家主体性的因素并揭示出了主体间互构的辩证关系。主体性是主体间互构的基础，同时主体间互构也反过来影响主体性的表述。公共舆论场和话语都蕴含于主体性互构的过程中并影响互构的结果。 最后得出本文结论：公共外交是一种交往行为，以主体间性为核心的交往理性是公共外交的本质特征。它意味着公共外交所有参与者的意见都应得到重视。公共外交以公众舆论为基础，以公共舆论场为交往媒介。公共舆论场具有四个的特点。公共外交的交往载体是话语，同时满足言语行为的三个有效性声称是公共外交达成共识、实现理解的必然要求。这就是交往行为理论指导公共外交实践而得出的一般原则。

In the traditional world, power-oriented international relations mostly focus on the military victories and economic powers. Whereas in today’s information age, politics concern whose story makes more convincing as well. Along with the rise of the global media and global civil society, the traditional diplomacy is being rewrittened by those non-traditional ways. Public diplomacy is one of them, which has gradually overturned the ways and targets in traditional diplomacy. However, the academics failed to reach a common consensus even in the most basic definition of public diplomacy. Now facing many unprecedented phenomena and problems, neither empirical study nor mainstream theory of international relations can provide reference. In hence, a broaden theoretical width is just around the corner. After a brief sketch of the literature, this thesis has identified two, related gaps in the literature. First, there is a lack of clear principles on how to engage in public diplomacy since the practically-oriented research is outnumbered the theoritical one. Second, there is a need for principles that has not been limited to individual countries, but can be reproduced and applied cross-nationally. Therefore, my question is this: Is there any general principles exist to guide us to conduct public diplomay more effectively? Following this question, this thesis is organized to test the hypothesis: inspired by Harbermas’ Communicative Action Theory, public diplomacy can be improved by developing a set of clear principles, that are cross-national in application. The thesis adopts a Critical Theory framework, and Communicative Action Theory is a type of critical theory for its shared principles of antipositivism method, achieving human emancipation through communicative rationality and the practical interest. Also, the thesis takes a mixed methods approach that is consistent with critical theory. As the cornerstone of this thesis, it starts with giving its own definition of public diplomacy after classification of current definitions “In accordance with the communicative rationality, public diplomacy is a bidirectional interchange activity based on both domestic and overseas publics, which involves in government and other social actors in order to guide and influence public opinion, shape good national image through multiple information channels.” And leave weight on several key factors of this definition. Especially, the thesis analyses the internal paradox between ‘soft power’ theory and public diplomacy principle. Then, the thesis gives a feasibility demonstration on Communicative Action Theory is do applicative to the research of public diplomacy since 3 aspects of conditions (ideal speech situation, lifeworld, public sphere) do exist in the reality of public diplomacy, which bulid the connection of public diplomacy and the Theory and provide assistance in providing an answer to fill the above gaps, in a coherent way. In addition, the next 3 main chapters are focused on answering the question that the thesis is aiming of. First of all, intersubjectivity is the most essential principles of public diplomacy. As a kind of communicative actions, public diplomacy is an intersubjective activity paying equally importance for all participators, which strongly opposite to the instrumental rationality and should not be summarized as subject to object. Thus public diplomacy is not a one-way soliloquy, but a two way interaction. Besides, there is also a case study for China’s news and broadcasting principle as ‘Different from domestic and overseas’, which first adopted among the 1960s and spread to foreign affairs. Although rarely mentioned nowadays, this principle is indeed unsustainable, especially under the context of public diplomacy. Moreover, public diplomacy is based on public opinion and take ‘public opinion sphere’ as its medium. Inspired by Habermas’ ‘public sphere’ theory, the thesis makes a point of ‘public opinion sphere,’ where public diplomacy is actual happens in. The prominent difference between ‘pubilic opinion sphere’ and ‘public sphere’ is whether the content is involved in national image or diplomacy strategy. Thus, Public opinion sphere shares 3 principles as publicity for participators, openness to institution, criticism on power. In order to incisively and vividly show how the publics’ opinion envoloves in public diplomacy from passively acceptor to stakeholders, a case study based on ‘Tokeyo’s massive recall in 2010 as crisis public diplomacy of transnational corporation’ has been taken. Last but not the least, discourse is the communicative carrier of pubic diplomacy. Public diplomacy break through the barriers between different languages. As a communicative action, it has to do with ‘speech acts’ and shared the same goal: to achieve understanding. Therefore, public diplomacy should follow the validity claims of ‘speech act’ as its discourse principles, which emphasis on sincereness, truthful, rightness. In conclusion, the hypothesis can be regarded as proven that public diplomacy can be guided by a set of clear principles inspired by the Communicative Action Theory.