Abstract: National sovereignty, as the fundamental guarantee for a country's independent development, embodies both the internal capacity to exercise supreme authority and the external right to enjoy equal status among nations, serving as the cornerstone for safeguarding national security, institutional stability, and the integrity of the governance system. Social governance, on the other hand, fulfills critical functions such as maintaining social order, delivering public services, and promoting fairness and justice, acting as a key pillar in advancing the modernization of the national governance system and governance capacity. In the context of Cyber-Physical-Social-Thinking (CPST) space, the national sovereignty faces threats such as blurred boundaries, cyber attacks, and ideological infiltration, and the traditional hierarchical social governance presents problems such as slow response, insufficient coordination, and limited public participation. This research proposes a framework for national sovereignty and social governance based on CPST space theory, systematically analyzing the collaborative logic between national sovereignty and social governance. On the one hand, national sovereignty evolves and extends in multiple dimensions under CPST space, exhibiting new cross-domain synergistic characteristics, and simultaneously, novel forms of sovereignty—particularly data sovereignty—are emerging as defining elements of contemporary governance; On the other hand, social governance is transitioning towards an intelligent governance model of “data perception-intelligent modeling-efficient decision-making”. This paper starts from the theoretical framework, sovereignty evolution, and social governance, and takes Hangzhou’s “urban brain” as an example to explore the feasibility of the transformation of social governance towards precision and proactivity. It will provide support for the development of national sovereignty resilience and the reform of social governance paradigms in the digital age.