In order to find an effective way to reverse the decline in the health of the oceans, the United Nations has decided to launch the "United Nations Decade of Ocean Science for Sustainable Development" (hereinafter referred to as the "Ocean Decade") since 2021. The Implementation Plan of Ocean Decade, which has been aceepted by the United Nations General Assembly on September 31, 2020, outlines the Ocean Decade’s vision of “building the science we need and the ocean we want”, and sets out the outcomes, challenges and objectives of the Ocean Decade, as well as mechanisms for implementation, governance, coordination, financing, monitoring and review. Described by the United Nations as a “once in a lifetime” programme, the Ocean Decade is a comprehensive United Nations-sponsored capstone programme for Ocean Megasciences that will build stronger science and technology innovation-based governance system at the global and national levels by inspiring and driving change in marine science. This will profoundly change human cognition and behavioural patterns towards the oceans, profoundly influence and even guide the evolution of the marine order, and have a great impact on the overall layout of regional cooperation in the oceans. It is suggested that China, guided by the concept of the “Marine Community with Shared Future”, actively participate in the Ocean Decade as a core means of deepening its participation in global ocean governance, and establish the Ocean Decade National Committee as soon as possible, and develop a Chinese programme of action to advance the sustainable development of the oceans and seas together with the international community.