With the acceleration of urbanization, urban disease problems are becoming increasingly prominent, and smart cities have gradually become an important direction for urban governance. However, the construction of smart cities still faces significant challenges in improving urban resilience. Therefore, the coordinated development of resilient cities and smart cities will become a key path to enhance urban sustainability. A comprehensive evaluation index system for urban resilience based on four dimensions including economy, ecology, society and infrastructure is constructed. The cross-sectional data of 15 sub-provincial smart cities in China in 2021 are selected, and their resilience levels are measured by entropy weight method, and gray correlation analysis is used to explore the influencing factors of resilience levels. The results show that:1) The overall resilience level of 15 sub-provincial smart cities in China is at a moderate lower level, showing a significant spatial differentiation pattern of "strong south and weak north";2) The urban resilience level is largely driven by economic resilience, among which the proportion of science and technology and education expenditures in public fiscal expenditures has the highest contribution rate to the improvement of resilience, followed by per capita disposable income, while the proportion of total import and export to GDP has the least impact. The results can provide theoretical support and policy reference for the integrated practice of smart city construction and resilience improvement.