The “single passport”, which is mainly implemented within the European Union, means that a financial institution is free to operate in other EU member states as long as the member state in which it is located approves it, and that other member states may not, in principle, impose additional regulatory requirements. Prior to the implementation of the “single passport”, EU financial institutions had to obtain permission from each member state in which they intended to conduct cross-border operations. As the core system of the EU single financial market, it has significantly contributed to the integration of financial services among EU countries, mainly by reducing barriers to the provision of cross-border financial services among member states. The unified implementation of the “single passport” system in the Guangdong-Hong Kong-Macao Greater Bay Area will provide institutional protection for the cross-border establishment and operation of financial institutions in Zhuhai and Macao, and will help the synergistic development of financial institutions in both places.