Abstract: Derived from the core arguments that the Court of Justice of the European Union invalidated the EU-US Privacy Shield in its Schrems II decision,this paper explores two different electronic data access and surveillance systems of the U. S. government under different law enforcement purposes. Although the system for general law enforcement purposes is relatively rigorous and standardized, the system based on national security purposes is lack of enough transpancy and too abroad on data surveillance scope, which leads the European Court of Justice to believe that it cannot meet the EU’s personal data protection standards, and therefore has a negative impact on the cross-border data transmission.

Key words: data access, national security, EU-US privacy shield