公共话语空间是哈贝马斯的重要理论，是指社会公众针对某一公共问题或公共事务，进行自由、平等的讨论，最终形成公共舆论的场所。随着社会高度的网络化和全球化，以网络媒介为载体的公共话语空间正在呈现出越来越重要的价值：公共话语的主体不再是单一的权威机构，而是社会各方面的参与者，他们共同构建和维护着公共话语，通过交往行动达成共识，推动着社会的进步和发展。但是，在网络媒介下，公共话语空间的建构和培育也面临着些许问题和挑战。如出现了公共性较弱、交往理性匮乏以及大众话语无法转变为公共话语等问题。因此，如何有效地建构公共话语空间，科学管理社会事务，有效引导公众对公共问题的理性讨论是政府亟待解决的问题。作为自媒体时代的产物，UGC模式下的社会题材纪录片实际上是官方对UGC影像的创造性使用，在重大突发事件或社会热点问题面前，无论是素材来自于自媒体平台用户拍摄的协同创作式纪录片，还是被平台采纳的由网络用户自主创作的个人微纪录片都是有效解决信息匮乏问题和引导舆论走向的关键。一方面，UGC的创作模式使纪录片的叙事视角更加多元，让公众更容易产生共情，另一方面，主流从个体化叙事中提炼出具有公共性的社会议题，并对其进行深入挖掘和表达可以引导观众更加理性、深入地参与公共事务的讨论和决策中。因此，本文将以UGC模式下社会题材纪录片为研究对象，对其形成的公共话语空间进行研究。以期为我国公共话语空间的建构和培育提供有效方法。本文共分为四章，第一章分别从UGC模式下社会题材纪录片概述和公共话语空间产生背景来对UGC模式下社会题材纪录片的形成进行论述。第二章为UGC模式下社会题材纪录片公共话语空间的观念与特征。观念部分从哈贝马斯公共领域出发的公共话语空间观念，再到将其中国化，形成中国特色公共话语空间，再到论述UGC模式下社会题材纪录片的公共话语空间观念。特征部分是以UGC模式下社会题材纪录片公共话语空间为研究对象，分析其“强时效性”“公共性与交往理性”特征。第三章为UGC模式下社会题材纪录片公共话语空间的主体与载体及话语表达。将从其公共话语空间内部最重要的三个构成，即话语主体、载体以及话语表达的特征特点进行论述。第四章为UGC模式下社会题材纪录片公共话语空间的表达范式及建构模式。将使用案例分析法对《武汉我的战役日记》进行分析，探讨网络空间中公共话语的表达的特点，和其如何发挥自下而上与自上而下相结合的舆论引导功能，形成既有秩序又有自由的中国特色公共话语空间。

The concept of public discourse space originates from Habermas's public sphere theory, referring to a space where the public can freely and equally discuss a public issue or affair, ultimately forming public opinion. With the increasing importance of the internet and globalization, public discourse spaces supported by online media are becoming increasingly valuable. The participants of public discourse are no longer solely authoritative institutions but also various social actors who collectively construct and maintain public discourse, reaching consensus through communicative action, and promoting social progress and development. However, under the online media environment, the construction and cultivation of public discourse space also face some issues and challenges, such as weak publicness, lack of communicative rationality, and the inability of mass discourse to transform into public discourse. Therefore, it is essential for the government to effectively construct public discourse space, scientifically manage social affairs, and guide the public's rational discussion of public issues.As a product of the self-media era, the UGC mode in social-themed documentaries is essentially an innovative use of UGC content by official channels. In the face of major emergencies or social hotspots, whether it is collaborative documentaries with material from self-media platform users or personal micro-documentaries created by internet users and adopted by the platform, both are key to addressing the lack of information and guiding public opinion. On the one hand, the UGC creative mode makes documentary narratives more diverse, allowing the public to empathize more easily. On the other hand, the mainstream extracts public social issues from individualized narratives, and by deeply exploring and expressing them, guides the audience to participate more rationally and deeply in public affairs discussions and decision-making. Therefore, this paper will take UGC-modeled social-themed documentaries as the research object and study the public discourse space formed by them, in order to provide effective methods for the construction and cultivation of public discourse space in our country.This article is divided into five chapters. The first chapter discusses the formation of social themed documentaries under the UGC model from the overview of social themed documentaries under the UGC model and the background of the emergence of public discourse space. Chapter 2 discusses the concept and characteristics of the public discourse space in social theme documentaries under the UGC model. The concept part is divided into the concept of public discourse space starting from Habermas' public sphere, then to sinicizing it to form a Chinese characteristic public discourse space, and finally to discuss the concept of public discourse space in social theme documentaries under the UGC model. The characteristic part takes the public discourse space of social theme documentaries under the UGC model as the research object, and analyzes its characteristics of "strong timeliness", "publicity and communicative rationality". The third chapter discusses the subject, carrier, and discourse expression of the public discourse space of social theme documentaries under the UGC model. We will discuss the three most important components within its public discourse space, namely the discourse subject, carrier, and characteristics of discourse expression. Chapter 4 is the expression paradigm and construction mode of the public discourse space for social theme documentaries under the UGC mode. We will use case analysis to analyze "Wuhan My Battle Diary", explore the characteristics of public discourse expression in cyberspace, and how it can leverage the public opinion guidance function of combining bottom-up and top-down to form a Chinese characteristic public discourse space that is both orderly and free.