As data becomes an emerging production factor, cross-border data flows are more frequent, cyberspace expands into the "fifth frontier", and the traditional concept of sovereignty extends to cyber space, data sovereignty emerges. Cross-border data flow has become the core of data sovereignty governance in China. This paper, from the perspective of data sovereignty protection, fully investigates the system and practice of cross-border data governance at home and abroad, analyzes the core governance models and conflicts based on jurisdictional principles, and summarizes the three cross-border data governance models, namely, intra-regional effect jurisdiction, global expansion jurisdiction, and centralized localization jurisdiction, as well as the legislative, judicial, enforcement and governance conflicts that exist among them. Thus, practical countermeasures and suggestions, in an attempt to provide references for China's data governance practice and safeguard China's data sovereignty, are proposed to optimize resource security, promote data resource flow, strengthen extraterritorial regulation, promote governance standardization, integrate into the international governance system, participate in governance dialogues, and engage in international cooperation, in order to optimize cross-border data governance in both directions, national and international.