当下，受到疫情影响的居家生活使人们更加依赖于数字平台，平台经济在全球范围内逆势高速增长。随着信息技术及商业应用的快速发展，平台企业出现了如“扼杀式并购”、“二选一”行为、算法共谋等垄断行为以及不正当竞争行为。为此，第十四个五年规划中提出要坚持鼓励竞争、反对垄断，建立健全覆盖事前、事中、事后全过程的监管机制；加强对反垄断和反不正当竞争的执法，防止资本无序扩张。因此，处理好公平竞争与创新活力之间的关系，完善与中国实际情况相符的新型互联网平台监管机制是建设全国统一大市场和推进国家治理体系现代化的必然要求。
基于此，本文运用文献研究法、案例分析法和比较分析法，通过对平台反垄断与监管相关的国内外文献梳理，首先对平台、反垄断、监管机制相关核心概念进行界定，以公共价值理论、协同治理理论以及行动者中心制度主义分析框架为理论基础，构建IAL监管机制分析框架。其次，在监管制度的基础上，探讨三类监管主体的行动逻辑与互动情况，结合监管环节，讨论监管主体的分工协作。同时，结合阿里巴巴“二选一”这一现实案例，探究中国平台反垄断监管机制面临的困境。最后，通过研究比较美国、欧盟在平台反垄断制度、监管主体、监管环节，分析可借鉴之处，完善多元主体共同参与，覆盖事前、事中、事后全过程的协同监管机制。通过研究，本文的主要结论如下：
第一，监管制度、监管行动者与监管环节方面的问题导致了当前中国平台反垄断的监管机制困境，主要体现在政策动态响应滞后、监管主体间存在协同壁垒以及监管环节缺失三个方面。
第二，针对中国平台反垄断监管困境，进行机制的完善。从制度层面出发，要构建高质量的制度体系，包括贯彻落实包容审慎的监管原则、完善反垄断指南相关配套细则；从行动者层面出发，要打破监管主体间的协同壁垒，加强协同监管，包括增进监管主体之间的紧密联系、激励平台企业开展自我合规；从监管环节层面出发，要健全全链条监管环节，包括强化事前动态监管、完善“双随机、一公开”事中监管；另外，中国还应积极参与平台经济国际规则秩序的构建，增强话语权和影响力。
第三，研究的主要创新是基于公共价值和协同治理理论，将行动者中心制度主义分析框架本土化，构建了IAL监管机制分析框架。研究局限性在于，虽然对平台反垄断监管制度、主体、环节构建的监管机制展开了探讨，但监管模式以及监管工具等要素也值得细化研究，也未根据平台分类进行针对性更强的讨论。另外，除了美国和欧盟，其他国家对于平台反垄断监管的改变与创新也同样值得借鉴，本文未能一一对比研究。未来研究可从监管模式、监管工具以及监管政策效果评估方向着手对平台反垄断监管机制进一步完善。

At present, the home life affected by the epidemic makes people more dependent on digital platforms, and the platform economy is growing at a high speed all over the world. With the rapid development of information technology and business applications, platform enterprises have appeared monopoly behaviors and unfair competition behaviors, such as algorithm collusion. The 14th Five-Year Plan proposes to adhere to encouraging competition and opposing monopoly, and establish and improve the supervision mechanism covering the whole process before, during and after the event. Strengthen the law enforcement of anti-monopoly and anti-unfair competition to prevent the disorderly expansion of capital. Therefore, properly handling the relationship between fair competition and innovation vitality, improving the supervision mechanism of new Internet platforms in line with China's actual situation. It is an inevitable requirement for building a unified national market and promoting the modernization of the national governance system.
Based on this, this thesis uses the methods of literature research, case analysis and comparative analysis to sort out the domestic and foreign literature related to platform anti-monopoly and supervision. Firstly, it defines the core concepts related to platform, anti-monopoly and regulation mechanism, and constructs the analysis framework of IAL supervision mechanism based on public value theory, collaborative governance theory and Actor-Centered Institutionalism analysis framework. Secondly, on the basis of the regulatory system, this thesis discusses the action logic and interaction of the three types of regulation subjects, and discusses the division of labor and cooperation of the regulation subjects in combination with the regulatory links. At the same time, from the case of Alibaba, combined with the analysis of the current situation, explore the difficulties faced by the anti-monopoly regulation mechanism of platforms in China. Finally, by analyzing and comparing the reference points of the United States and the European Union in the platform antitrust system, regulatory actors and regulatory links, improving the collaborative regulation mechanism with the joint participation of multiple subjects and covering the whole process before, during and after the event. Through the research, the main conclusions of this thesis are as follows:
Firstly, the problems of regulatory system, regulatory actors and regulatory links have led to the dilemma of the current regulation mechanism of China's platform anti-monopoly, which is mainly reflected in three aspects: the lag of policy dynamic response, the existence of collaborative barriers among regulatory actors and the lack of regulatory links.
Secondly, improving the regulation mechanism according to the dilemma of platform anti-monopoly in China. From the perspective of institution, we should build a high-quality institutional system, including implementing the inclusive and prudent supervision principle and improving the relevant supporting rules of the anti-monopoly guidelines. From the perspective of actors, we should break the collaborative barriers between regulators and strengthen collaborative supervision, including enhancing the relationship between regulators and encouraging platform enterprises to carry out self-compliance. From the aspect of regulatory link, we should improve the whole chain regulatory links, including strengthening dynamic supervision in advance and improving in process supervision. In addition, China should also actively participate in the construction of international rules of platform economy and enhance its voice and influence.
Thirdly, the main innovation of the research is to localize the Actor-Centered Institutionalism analysis framework and build the analysis framework of IAL regulation mechanism based on public value and collaborative governance theory. The limitation of the thesis is that the regulation mechanism of the anti-monopoly regulatory system, actors and links of the platform is discussed, there are still elements such as supervision mode and supervision tools that deserve detailed research, and more targeted discussion according to the classification of the platform is not considered. In addition, in addition to the United States and the European Union, the changes and innovations of platform anti-monopoly regulation in other countries are also worthy of reference, and this thesis fails to make a comparative study one by one. Future research can further improve the anti-monopoly regulation mechanism of the platform from the direction of supervision mode, supervision tools and the effect evaluation of supervision policies.