High- speed rail as the infrastructure for material and information exchange is important channels in urban agglomerations that connect urban centers and facilitate urban expansion, and urban agglomeration is a greater metropolitan area whose internal separation is reduced by high- speed rail system. This study used passenger flow data of 380 sites in the Yangtze River Delta high-speed railway system to construct a 20 by 20 matrix for examining connections between cities in the Yangtze River Delta Urban Agg...