The marine economic demonstration zone is a key measure for China to implement the strategy of building a strong maritime country，promote the optimization of the marine industrial structure，and accelerate the construction of new quality marine productivity. Analyzing and elaborating on the effects of marine economic demonstration zones on the optimization of the marine industrial structure is of great significance. Based on macro ocean economic data，explain the practical effects of ocean economic demonstration zones on optimizing the marine industry structure of typical coastal provinces. The results show that：① China’s marine industry structure continues to optimize，demonstrating strong resilience，and the construction of marine economic demonstration zones is becoming increasingly perfect；② Using typical coastal provinces as research cases，it was found that marine economic demonstration zones have a positive and significant effect on optimizing the marine industry structure，and there is a lag Based on the development process of typical provinces，summarize general experience in the development of marine industry，mechanism innovation，and policy regulations. Suggestions are proposed from the perspectives of strengthening policy implementation process，paying attention to policy lag phenomenon，and expanding funding sources，providing reference for optimizing the structure of the marine industry.