In the pre-Internet and pre-digital era，sovereignty issues related to information and communication mainly involved in only several specific kinds of information which may threaten national security or economic safety. The emergence of internet and digital economy brought about two changes. The first change is that the national boundaries in the sense of physical space are broken by the interconnection of networks. The second is that data and information have become resources like “petroleum” and be called “digital oil”，which makes personal information which belongs to “private domain” linked to national interests. These changes challenged the exercise of traditional sovereignty，and expanded the connotation of sovereignty. This article traced the concept of sovereignty and the role of communication in the formation of sovereign states，and analyzed the sovereignty issues involved in communication in the pre-digital era. Then，it discussed the expansion of the sovereignty boundaries brought by the revolution of information technology. Based on Carl Marx’s people’s sovereignty theory，this article proposed that in order to effectively deal with the long-arm jurisdiction of cyberspace and data from other countries，it is necessary to decentralize the control of data，and improve the ability of individuals to control and determine their own data. It is an available approach to defend national sovereignty in cyberspace and data by empowering individual information subjects.