Continuously optimizing the doing business environment in the ocean field is an important measure to accelerate the construction of a modern ocean city. However，existing studies are insufficient in exploring the influencing factors and condition combinations of the doing business environment in ocean cities. Based on the ecosystem theory，this study investigates the connotation and constituent elements of the doing business ecosystem in ocean cities. Taking 32 ocean cities across the country as typical cases and using the fuzzy-set qualitative comparative analysis（fsQCA）method，it explores the configuration effect of ecological elements of the doing business ecosystem in ocean cities and the multiple paths for optimizing the business environment in ocean cities. The study shows that a single ecological factor is not a necessary condition for optimizing the doing business ecosystem of an ocean city. Each ecological factor is interdependent and forms three configurations that constitute a high-level doing business ecosystem，including the soft power shaping type supported by basic conditions，the transformation and development type dominated by dual elements of technology and culture，and the market-promoting type driven by dual elements of technology and culture. The study also identifies eight configurations that result in non-high-level business environment ecology，explaining the main reasons for the poor doing business ecosystem in some ocean cities.