Abstract: Data plays an increasingly important role in the Internet era. Cross-border data flow is related to national security, social development and individual interests of citizens. At present, countries build cross-border data flow models that are conducive to national security and development by promoting data localization and strengthening data sovereignty Under the national security perspective, to build the data system of nationality, for some data that could affect national security information collection, before its cross-border flows, clarify its nationality attribution and jurisdiction, to carry out the data network sovereignty ownership, the greatest common divisor of cross-border flows of international cooperation, seeking data in ensuring the state data entry exit Under the premise of effective control, the dual goals of cross-border data security and free flow are realized