Abstract: The integration of ports in the Yangtze River Delta is an inevitable trend of regional integration. Promoting the integration of ports in the Yangtze River Delta can enhance the international competitiveness of the port group in the Yangtze River Delta. In order to analyze the integration of ports in the Yangtze River Delta from the perspective of the maritime producer services, this paper uses the data of Lloyd’s maritime directory from 2006 to 2018, as well as the Talor “Interlocking Network Model” and community structure to analyze the spatial-temporal pattern of low-end, mid-end and high-end maritime producer services and the spatial connection of port cities in the Yangtze River Delta. The results show that: (1) The three types of maritime producer services in the Yangtze River Delta showed rapid but uneven development. The low-end maritime producer services are still the development focus, but it has begun to transform to the high-end maritime producer services. (2) The low-end maritime producer services present a distribution pattern of “along the river and along the coast” with Shanghai as the center, and the mid and high-end maritime producer services form an obvious port hierarchy. (3) The cooperation pattern has begun to take shape in the Yangtze River Delta. The port cooperation in the mid-end maritime producer services is the closest and the degree of integration is the highest. The degree of closeness of collaboration or degree of integration, from high to low, are: mid-end, high-end, and low-end. (4) Jiangsu and Zhejiang have formed obvious community structure respectively, which has intensified the competition among the provinces. The integration degree of port cities is limited by the provincial administrative divisions, and has not yet broken through the administrative barriers. How to break the administrative barriers between the provinces has become the key to promoting the high-quality integration of the ports in the Yangtze River Delta. Furthermore, Shanghai’s “siphon effect” in high-end maritime producer services is obvious. Ports of different grades should complement each other, form dislocation competition, and promote the integrated development of ports in the Yangtze River Delta with higher quality.