Marine resource endowment is a significant supporting factor for the sustainable development of the marine economy. It primarily reflects the sustainable development level of the marine economy in a particular area. Based on literature analysis and expert consultation, this paper establishes an index system of potential evaluation of marine resource endowment for the sustainable development of China's marine economy, where the Analytic Hierarchy Process is used to determine the weight of each index within the system, thus securing the distribution of each index. This paper also evaluates the development potential with 11 coastal provinces (municipalities) being empirical research objects using a fuzzy comprehensive evaluation method. The result is that the support potential of the resource endowments of marine minerals, marine space, marine tourism, and marine life (aquatic products) for the sustainable development of China's marine economy has been declining gradually.