This study explores the interactive mechanisms between urbanization synergy and blue economy upgrading in global maritime center city construction, taking China’s coastal cities (Qingdao, Shanghai) and Middle Eastern hubs (Dubai, Jeddah) as cases. Based on policy texts, statistical data (2022–2024) and in-depth interviews, it constructs an evaluation framework covering industrial integration, technological innovation, ecological governance and institutional support. Results show that China relies on "port-city-industry" linkage and technological agglomeration, while the Middle East emphasizes policy liberalization and tourism-energy integration. Both face challenges of ecological pressure and industrial mismatch. It proposes targeted paths: China should enhance technology conversion, while the Middle East needs to strengthen ecological regulation.