Based on the panel data of 282 cities in China from 2011—2021, the impact of digital economy on carbon emission intensity was empirically tested. It is found that the development of the digital economy can significantly reduce the intensity of urban carbon emissions, and there is a "U-shaped" characteristic of first decreasing and then increasing. Using the quality of industrial structure upgrading, the quantity of industrial structure upgrading, and green technology innovation as moderating variables, it is found that the quality of industrial structure upgrading strengthens the negative effect of digital economy on carbon emission intensity, while the quantity of industrial structure upgrading and green technology innovation weaken this negative effect.