Conserve and sustainably use the oceans, seas and marine resources for sustainable development has been written into UN’s 2030 Agenda for Sustainable Development, which has become one of the hot issues in the international community, and some international organizations and coastal countries have initiated related researches. The paper summarizes domains of the marine economy and research progress. Then it puts forward seven major factors that will influence the global marine economic development in 2030, namely, prospect of the global economy, technological innovation and progress, population growth and related issues of urbanization and aging, changes in the world’s energy structure, geopolitical risks, the interplay of climate change and ocean, and the implementation of ocean economic policies. Furthermore, the paper analyzes the trends for the development of global marine industries and proposes five suggestions to promote the sustainable development of China’s marine economy.