Abstract: As the impacts of climate change and human activities intensify, water systems of coastal cities are under mounting pressure, therefore, exploring water security issues and countermeasures for enhancing resilience in coastal cities are of profound significance for sustainable development. Focusing on coastal cities, this paper systematically reviews the current situation and evolution mechanisms of water security in coastal cities, and explores the concept and framework for enhancing water security resilience. Urban water security encompasses multiple aspects such as water resource supply, water disaster control, water environment protection. The environment, structure, and functions of the water system serve as the supporting elements of water security. Natural geographical characteristics, land - sea interactions, degree of urbanization, climate change, etc., make water security issues in coastal cities more complicated. Currently, the primary challenges pertain to the balance between water resource supply and demand, the generation and management of stormwater, as well as the integrated governance of pollution. Regarding the enhancement of coastal cities resilience, which is an issue of complex system optimization, it is necessary to conduct systematic considerations based on land - sea coordination. To build a framework for enhancing water security resilience, it is necessary to focus on key aspects such as resource, disaster, and ecological security, and the effectiveness evaluation of resilience needs to consider the processes from pre-disaster, during-disaster to post-disaster. The overall framework could be established around aspects such as theoretical, technological, operation and maintenance, governance, and institutional innovation, etc. Enhancing the resilience of urban water security is an important part of China's current national strategies and security. This study can offer references and theoretical references for the comprehensive governance of water - related issues in coastal cities.