**4. Conclusions**

Combining the relevant index data of the research cities, and using the urban system vulnerability evaluation index model, we calculate the 2018 Beijing-Tianjin-Hebei urban agglomeration, the Yangtze River Delta urban agglomeration and the Guangdong-Hong Kong-Macao Greater Bay Area to obtain the vulnerability of each city in 2018 Sex index. The results show that the central cities and economically underdeveloped cities of the three major urban agglomerations are relatively vulnerable areas in the urban agglomerations, and are areas with low sensitivity and high response. According to the clustering results, the vulnerability of the urban system can be divided into four levels. In the Guangdong-Hong Kong-Macao Greater Bay Area, Guangzhou is a very vulnerable area, and Shenzhen is a vulnerable area. Among the city clusters in the Yangtze River Delta, Shanghai and Suzhou are vulnerable areas; Hangzhou and Nanjing are vulnerable areas. In the Beijing-Tianjin-Hebei urban agglomeration, Beijing is a very vulnerable area, and Tianjin and Tangshan are low-vulnerability areas. The vulnerability structure of the central cities of China's three major urban agglomerations is obvious. Their economic development is in a leading position in urban agglomerations and countries. From the perspective of urban infrastructure, cities have a strong ability to deal with vulnerabilities. To this end, this paper proposes measures to respond to climateadaptive large urban agglomerations in terms of enhancing the carrying capacity of central cities and strengthening the application of pan-smart city technologies.
