With the continuous development of urbanization, and increasing uncertainties and risks, resilience has become an important criterion for urban safety. As a dynamic and open spatial system, the urban system presents typical complex features. Thus, the understanding of urban resilience from the perspective of complex systems theory is helpful to achieve a full understanding of the composition and functioning mechanism of urban systems, and to then improve the scientific nature of urban system cognition and research. In this article, the literature on urban resilience is first reviewed, and it is found that the related research on resilience assessment has yielded some assessment methods. Then, based on complex adaptive systems (CAS) theory and combined with its seven basic characteristics, the basic characteristics of complex urban systems are summarized from the perspective of the principle of the urban system action mechanism. On this basis, a framework of complex urban systems is constructed from three aspects, namely the system environment, system elements and system structure, and the assessment methods of the urban system resilience for each aspect are explored. This study not only expands the research on urban system resilience assessment, but also provides a reference for urban safety development and resilience improvement.

随着城市化的不断发展，不确定性和风险的不断增加，适应力已成为城市安全的重要标准。作为一个动态，开放的空间系统，城市系统呈现出典型的复杂特征。因此，从复杂系统理论的角度对城市弹性的理解有助于全面了解城市系统的组成和运行机制，进而提高城市系统认知和研究的科学性。本文首先回顾了有关城市弹性的文献，发现相关的弹性评估研究提出了一些评估方法。然后，基于复杂自适应系统（CAS）理论并结合其七个基本特征，从城市系统作用机理的原理出发，总结了复杂城市系统的基本特征。在此基础上，从系统环境，系统要素和系统结构三个方面构建了复杂的城市系统框架，并探讨了各个方面的城市系统弹性评估方法。该研究不仅扩展了城市系统抗灾能力评估的研究，而且为城市安全发展和抗灾能力提高提供了参考。并探讨了各个方面的城市系统弹性评估方法。该研究不仅扩展了城市系统抗灾能力评估的研究，而且为城市安全发展和抗灾能力提高提供了参考。并探讨了各个方面的城市系统弹性评估方法。该研究不仅扩展了城市系统抗灾能力评估的研究，而且为城市安全发展和抗灾能力提高提供了参考。