To foster a new development paradigm, the Yangtze River Economic Belt serves as a crucial hub connecting the domestic and international circulations. As the leading port and core node of the Yangtze River Economic Belt, Shanghai Port's strategic role as one of the most critical infrastructure has become increasingly prominent. The Shanghai International Shipping Center is facing a bottleneck of spatial resource constraints in upgrading its service capacity. This paper evaluates port operational efficiency by constructing models for port service intensity, waiting probability, and queuing theory. It quantifies the impact of resource constraints using a ship loss rate model under different system capacities, while comparing development strategies of typical domestic and foreign ports to analyze the core challenges confronting the Shanghai International Shipping Center. Model analysis indicates that the structural contradiction between port service demand and spatial resource supply has become a key constraint on its high-quality development. Looking ahead, the expansion and upgrading of port-shipping resources and optimizing spatial resource allocation will enable the Shanghai International Shipping Center to effectively unleash the advantages of direct river-sea transportation, significantly improve port service capacity and the navigation efficiency of the Yangtze River Golden Waterway, and reduce the comprehensive logistics costs of the whole society. This development path will not only promote the green transformation and digital-intelligent upgrading of the shipping industry but also strengthen the country's supply chain security and expand high-level opening-up, laying a solid foundation for the long-term and sustainable development of the Shanghai International Shipping Center.