The conservation of marine biodiversity and the sustainable use of resources beyond national jurisdiction have attracted widespread attention internationally. The conservation and sustainable use of marine biodiversity in areas beyond national jurisdiction has a major impact on the global environment and human development, but existing legal norms are still immature. From the perspective of constructing a new International agreement under the framework of the United Nations Convention on the Law of the Sea, the necessity and feasibility of the new agreement are analyzed, and the four key issues of the most controversial agreement at the international conference are discussed. In addition, in addition to improving the domestic marine biodiversity protection legislative framework, China should be also more actively involved in the negotiation and formulation of the international agreement legislation, ensuring its own rights and interests in the sea areas under national jurisdiction and safeguarding the maritime interests of developing countries, and strive to maintain the balance of marine ecosystems.