城市体系具有规模——等级分布特征，创新在城市体系中的扩散表现为多种扩散模式。关联分析表明，创新扩散系统的四大要素与城市体系构成之间存在着密切的空间关联机理。基于回归、聚类、典型相关等方法的实证分析发现，长三角城市的创新能力与城市规模都具等级特征，两者之间有较强的相关性，创新在长三角城市间的空间扩散次序与城市等级结构具有一致性，呈明显的等级扩散特征。

            The cities in urban system meet the rank-sized rule. Innovation diffusion in urban system has several modes, such as hierarchical diffusion, contagious diffusion, and so on. The correlative analysis indicates that there is a clear correlation mechanism between innovation diffusion and urban system. Empirical analysis shows that both the innovation capacity and city size have hierarchical characters and are highly correlative in the Yangtze River Delta. The spatial diffusion order of innovation is consistent with the urban hierarchical structure. The spatial diffusion in urban system mainly belongs to hierarchical diffusion.