With the intensification of global climate change and the frequent occurrence of extreme weather events, the critical infrastructure of cities is facing increasing risks and challenges. This paper explores the importance of improving the resilience of critical infrastructure in large cities in an era of climate crisis. By analyzing different types of critical infrastructure and their impact on urban security, this paper points out that once the urban infrastructure such as transportation, power, communication, water resources is damaged, it will seriously affect the normal operation of the city. Combining the case of Zhengzhou's "July 20" rainstorm disaster in 2021 and Zhuozhou's rainstorm event in 2023, this paper reveals the main problems facing the current infrastructure, including inadequate design and maintenance, lagging emergency response mechanism and difficulties in inter-departmental coordination. Therefore, this paper proposes improvement measures such as optimizing the construction of critical infrastructure, strengthening the emergency management mechanism, and enhancing the capacity of resource reserve and dispatch, so as to improve the resilience of critical infrastructure in extreme climates and ensure urban safety and sustainable development. The paper emphasizes that building smarter and more adaptable critical infrastructure systems will be a key direction to deal with future disasters.