Networking development of urban agglomeration is one of essential characteristics of the integrative growth in the Yangtze River Delta region. In this paper, social network analysis (SNA) and kernel density estimation are combined through gravity model and structural model of urban agglomeration’s economic networks is constructed. After an empirical study on 25 cities in the Yangtze River Delta, network density, kernel density distribution and cohesive subgroups of economic network in Yangtze River Delta urban agglomeration are analyzed, to innovatively research the structure and networking development patterns of urban agglomeration. It is indicated by the results that a relatively mature net association has formed among cities in the Yangtze River Delta, while the centrality between cities in the network is imbalanced, so that relevant suggestions on network optimization of economic relation among Yangtze River Delta urban agglomeration are proposed.