With the globalization of the digital economy and the further development of cross-border trade, the cross-border flow of data is more and more frequent. In order to promote the secure sharing of cross-border data, this paper reviews the definition of cross-border data and the concepts of classification and grading, then gives the analysis and comparison of the current situation of cross-border data classification and grading in six main countries systematically, which is from the perspective of laws, regulations, and applications. With the construction requirements of the free trade ports in China, combined with existing laws and standards in China, a scheme proposal and its implementation process of the classification and grading of cross-border data in the free trade port are presented to improve the problems of weak operability and high costs of evaluation standards and existing technology deficiency for cross-border data. This study presents a comprehensive approach to the development of Chinese cross-border data regulations, with a particular focus on their role in facilitating the growth of the digital economy in free trade ports.