Based on panel data from 277 cities in China from 2003 to 2019, this paper uses a multi-period difference-in-differences (DID) model to analyze the effect of civilized city construction on urban carbon emission intensity. The findings of the research are as follows: Firstly, the construction of civilized cities is conducive to curbing the carbon emission intensity of cities, and the construction of civilized cities has reduced urban carbon emission intensity by 14.5%. Secondly, this inhibitory effect can be achieved by optimizing the industrial structure, reducing urban energy consumption, and improving technological innovation. Thirdly, the impact of civilized city construction on urban carbon emissions varies significantly depending on urban location, urban administrative level, urban resource endowment, and urban cultural tourism resources. In addition, the construction of civilized cities in China has resulted in a reduction of carbon emission intensity by 13.2% in non-resource-based cities, and tourist cities have witnessed a 16.8% decrease in carbon emission intensity due to the construction of civilized cities. Finally, based on the analysis results, some suggestions are put forward for promoting the construction of civilized cities in China to reduce carbon emission intensity.