Abstract:    In the context of China facing the challenges of "fundamental improvement of ecological environment" and "carbon peak and carbon neutrality" simultaneously, whether the digital economy, as a new impetus for high-quality economic development, can effectively promote the synergistic reduction of pollution and carbon emissions (SRPCE) is an important issue that deserves to be explored in depth. Using comprehensively the panel regression model, the mediating effect model and the spatial Durbin model, this paper empirically examined the impact of the digital economy on the SRPCE based on the panel data of 278 Chinese cities from 2011 to 2021. The results showed that: (1) digital economy can effectively promote local SRPCE, and the effect gradually increases with the level of digital economy promotion; (2) Green technology innovation plays a mediating role in the facilitation of the digital economy on the SRPCE; (3) The spatial spillover effect of the digital economy on the SRPCE in neighbouring cities from a spatial perspective showed a change from "neighbour-beggar" to "neighbour-companion" (U-shaped change), and the spillover effect decreases with the increase of geographic distance, which is only significant within a geographical area of 100-400 km; and (4) green technology spillover is an important mechanism leading to the U-shaped change. This study will provide empirical evidence on how the digital economy influences the SRPCE, as well as a practical reference for the policy design and realization path for interregional synergies in pollution and carbon reduction. 

Key words: digital economy, synergistic reduction of pollution and carbon emission, green technology innovation, green technology spillover