Abstract: The security of cross-border data transmission accompanied by the "Belt and Road" digital economic development is very important and has become the focus of a new round of international economic and trade rules game. In order to balance the relationship between "data protection" and " data value mining", meet the growing information needs of countries along the Belt and Road, and realize the legal response corresponding to the vigorous development of their digital economy, this paper attempts to comb through the map of the existing data transmission mechanisms in Europe and the United States, analyze the operating differences of the current governance mechanism, and propose solutions to the problem: (1) Build a Chinese-led "digital WTO" system to enhance the operability of the digital economy of all countries. Cultivate and build the "Belt and Road" international data trading center, establish a judicial cooperation mechanism, improve the transparency of cross-border data transmission of the Belt and Road, support digital free trade, oppose digital protectionism, design a two-way data transmission governance mechanism of the Belt and Road, lead the formulation of rules for countries to participate in the "Belt and Road" digital economic development; (2) Increase the number of countries and regions under the jurisdiction of the Belt and Road Digital Economic Development Territory, determine the reasonable connection points for data transmission, expand the scope of data jurisdiction types, and reasonably confirm the types of data jurisdiction; (3) Refine territorial data classification management, increase the "Belt and Road" national data security management guidelines, design comprehensive "full protection" evaluation standards, pay close attention to the development trend of digital economy technology; (4) Strengthen the organization of internal data protection institutions in countries along the route, and form law enforcement agencies that cooperate and share data in cross-border transmission.