The marine economy, as an important driving force for economic development in coastal countries and regions, is now generally accepted by the academic world. This article examines the economic impact of the marine industry on China’s coastal provinces and cities and focuses on the narrowing development gap the marine industry faces in the coastal provinces and cities to promote the coordinated development of China’s coastal zone. It will further analyze the spatial and temporal differentiation of the marine industry along with what has driven China’s regional economic growth from 2006 to 2015. The research has proven that the marine economy certainly has a tremendous impact on provincial economic growth in coastal provinces (cities) and that even its degree of promotion is different in different cities. Further findings state that the contribution rate of the marine economy to the provincial economy in Tianjin, Shanghai, Fujian, Shandong, Guangdong, and Hainan is higher than the national average rate. Related findings are conducive to gain a better understanding of how development can be balanced and what best scientific decision-making practices can be utilized by policy-makers and planners in China.