中文摘要：

本文从城市等级到城市网络转化的研究视角，在文献回顾的基础上，对城市网络研究的转变模式、网络结构特征、单个城市与城市网络的关系等方面进行了探讨。研究认为：（1）从城市单体来看，可从城市等级的中心性与城市网络的节点性组成四象限分析城市的特性并对城市进行归类；（2）从城市联系通道来看，城市等级到城市网络经过了单向与非对称、通道少到双向、通道多样化的转变，作者从联系方向、联系主体、联系大小、联系空间、联系途径等方面进行了对比研究；（3）从城市外部联系角度来看，可从点、线、网络结构方面进行城市网络的分析研究；（4）结合城市网络特征，单个城市与城市网络的基本关系可从节点、关系通道、联系强弱、聚类特征、抗风险性等方面进行分析。

英文摘要：

With an eye to the research transformation from hierarchy structure to city network, this paper overviews the ancient studies about urban system, and then discusses the transformation contents of city network studies, the characteristics of network structure, the relationships between each city and other cities in city network, etc.. The results and conclusions are as follows. （1） From city node perspective of each city, we can combine the centrality of city hierarchy with the nodality of city network, and analyze cities＇ features from four quadrants consisted of centrality and nodality of cities; （2） From city relations and trajectories perspective, the transformations are changing from the characteristics of one- directional way and asymmetric to bidirectional way and diversified trajectories. We compare the two theoretical methods from many aspects including linkage direction, relation subject, the volumes, relational space, and the paths, etc.; （3） We elaborate the city network structure from the perspectives of points, lines, and subgroups; （4） According to the basic Waits of city network, the relations between each city and others in city network can be analyzed including nodes, Irajectories, volumes, cohesions, and risk resistance capacity.