Combining technology with finance is the focus of supporting economic structure adjustment, and environmental benefits are also the proper meaning of the policy. Using the panel data of 274 cities in China from 2006 to 2017, this paper examines the impact of the Science and Technology Finance Policy (STFP) on carbon emission intensity in pilot cities and the transmission mechanisms through the difference-in-differences method and further explores the impact of STFP on the carbon emission intensity in neighboring cities. The results show that (1) STFP has significantly reduced carbon emission intensity in pilot cities and has dynamic effects, which gradually increase over time. There is significant heterogeneity in the carbon emission reduction effect of STFP, which produces stronger policy effects in first and second-tier cities and cities with higher information levels. (2) STFP achieves carbon emission reduction effects through three main pathways: the total factor productivity improvement effect, innovative elements agglomeration effect, and industrial structure optimization effect. (3) The STFP and national e-commerce demonstration policy have an interactive effect, and the two jointly contribute to the reduction in carbon emission intensity. From the perspective of a spatial effect, STFP has a radiation effect; that is, STFP not only reduces local carbon emission intensity but also curbs the carbon emission intensity in neighboring areas.
