Platform monopoly is one of the prominent problems exposed in the rapid development of the digital economy. It is necessary to clarify the formation mechanism of platform monopoly to prevent the disorderly expansion of digital capital and guide the benign development of the digital platform. In view of the fact that platform rent is the main way for the digital platform to make profits, based on the generation of digital labor and its characteristics, the generation and characteristics of digital platform rents are explored, which provides a feasible path for correctly understanding and treating platform monopoly. Based on the methodology of the land rent theory of Marxist political economy, this paper comprehensively analyzes the “general” and “special” aspects of platform rent. Firstly, by tracing the concept of the “platform”, the characteristics of the information and its key role in the platform can be clarified. While combined with the concept of “rent in general” abstracted from Marx’s land rent theory, the theoretical connotation of platform rent can be well-explained: it originates from the platform’s monopoly of information ownership, it’s manifested as the differentiated productivity effect inside and outside the platform, and it endures because of the scarcity of quality platforms which leads to the monopoly of management rights. Above is the “general” aspect. Then, the innovation of digital technology changes the labor process, and aimless labor, non-material labor objects and complex labor materials become a reality, which constitutes the main characteristics of digital labor. According to Marx’s combing of the evolution history of land rent, different forms of rent reflect the way of labor under different technical conditions. Therefore, digital labor makes the digital platform rent directly manifested as the data rent, which shows a trend of series accumulation and polarization and also has a certain technical barrier and audience inertia. This is the “special” aspect. In addition, the different forms of digital platform rent are in a dynamic historical correlation, and inevitably evolve into monopoly rent. On this basis, this paper proposes a bilateral monopoly model to explain the monopoly mechanism of the digital platform: on the one hand, the digital platform implicitly collects data rent from the non-operating users, and is in a natural monopoly position because of the product form of the rent. On the other hand, the platform collects explicit currency rent from the operating users, which quickly becomes the monopoly rent due to the market competition characteristics of the digital platform. Then, some digital platforms which are in the privileged position of monopoly will constantly try to build an ecological monopoly, in order to continuously reproduce the monopoly relationship. Based on the above analysis, the effective regulation of the digital platform monopoly should be multifaceted: in the short term, the adjustment of the tax structure should be emphasized, and some new types of taxes, such as the digital resource tax, should be considered. In the medium term, the orders of the digital economy, which includes the order of usage, competition and operation, are supposed to be well-guaranteed. In the long run, the development of public information platforms should be gradually promoted, because the fundamental way to solve the practical problem of digital platform monopoly is to realize the public possession of digital platforms and data elements.