The continuous prosperity of digital governance has accelerated the informationization wave at the global range. Issues such as data store，use，protection，mobility mechanism have gradually come out，to name but a few. In particular，the cross-border data flows has been an issue that would further escalate the governance difficulty. The cross-border data in flow is relevant to the legal regulation on the issues such as information protection，data security，which has already been a global consensus. The cross-border data flow is both an issue of domestic governance and an issue in international law. The Guangdong-Hong Kong-Macao Greater Bay Area is featured by the “one country，two systems three scopes of law”. The mobility of cross-border data has been influenced by multiple factors. Internally，the regional mobility of the key factors shall be made while externally the connection with the global market of key factors and the rule system shall be made. An effective path shall be explored to promote the regional cross-border data flows. The international community has applied some good practices on that. UN advocates a more open and inclusive global digital system. US has constructed the conditional liberalism mode. EU has taken the governance mechanism on cross-border data flow by identifying the internal or external data from the continent. The cases have provided the beneficial experience to the cross-border data governance in the Guangdong-Hong Kong-Macao Greater Bay Area. However，the cross-border data governance in the Bay Area is still faced with several obstacles and dilemmas. In the next step，the Bay Area shall learn the advanced experience，coordinate the dual governance mechanism internally and externally，and fulfill the mobility mechanism on the cross-border data in the Bay Area through diversified paths.