Based on the panel data of 259 cities across China from 2011 to 2019, the study investigates the long-run impact of digital economy on regional pollution intensity by employing multiple models. The estimation results reveal that (1) the relatively heavily polluted areas are concentrated in the north, especially in the northeast of China; the overall pollution intensity is decreasing year by year at the national level; (2) the development of digital economy can significantly contribute to the reduction of regional pollution intensity and it has a statistically significant negative spatial spillover effect on the pollution intensity of neighboring cities; (3) mechanism analysis shows that the development of digital economy not only has a direct effect on the reduction of pollution intensity but also promotes the reduction through the channel of industrial structure upgrading and green technology progress; (4) the results of threshold model suggest that as the level of development of the digital economy increases, its marginal inhibitory effect of promoting the decrease in pollution intensity will diminish; (5) heterogeneity analysis shows that the development of digital economy makes the strongest marginal contribution to pollution intensity reduction in the northeast region. Finally, the conclusions remain valid after controlling for exogenous shocks such as "smart city" policy, various robustness, and endogeneity tests.