In view of the limitations of the traditional “port-industry-city” three-dimensional analytical framework in capturing the synergy mechanisms among key elements such as routes,shipping enterprises,information,and finance,a “seven-in-one” synergy development analytical framework is proposed comprising port,route,shipping enterprise,cargo,information,finance,and government.Within this framework,the intrinsic interrelationships are systematically examined from three dimensions:infrastructure,operational optimization,and institutional safeguards.By a multi-case comparative approach,Guangzhou Port,Ningbo-Zhoushan Port,and Rizhao Port are selected as representative cases for empirical analysis.The results indicate that the seven-in-one synergy mechanism can substantially improve overall port efficiency.Specifically,Guangzhou Port reduces customs clearance time by 60% through the “bay area one-port access” model;Ningbo-Zhoushan Port shortens average vessel waiting time to 8 h by leveraging the “port brain” platform;Rizhao Port reduces port clearance time to 12 h via the “smart port cloud brain” system.The “seven-in-one” synergy mechanism extends the scope of the traditional “port-industry-city” tripartite framework by incorporating a more multidimensional and dynamic perspective.It provides a more systematic analytical framework for enhancing port performance,strengthens the competitiveness of Chinese ports within global supply chains,and offers both theoretical insights and practical references for port development under the Belt and Road Initiative.