Abstract: The procedural obligations of environmental impact assessment (EIA) have been established in international law, while the substantive standards are mainly implemented by states referring to international “soft law”. The formulation of the relevant provisions of the coming agreement on the biodiversity in the areas beyond the jurisdiction of states (ABNJ) under the UNCLOS should adhere to the ‘soft regulation mode’ based on the principle of proceduralism; And the EIA of ABNJ should be carried out under the guidance of domestic law and with reference to international norms, while the member states enjoy the independent decision-making power. This “transnationalism” approach, which states dominate the implementation and make decisions independently, can be embodied in the extraterritorial application of domestic law based on “impact oriented”; As the interaction between regional marine EIA rules and global mechanism will have a certain impact on the future ABNJ system, China could actively promote the new BBNJ agreement and gradually embed the EIA in regional maritime negotiations.