Abstract: Under the dual goals of achieving economic growth and carbon emission reduction in China, the new digital infrastructure provides a new opportunity and a practical path for improving regional carbon productivity. Based on the latest and available panel data of 108 cities in the Yangtze River Economic Belt (YREB) from 2009 to 2019, the paper used kernel density estimation model, spatial durbin model, mediation effect model to explore the spatial evolution trend of the new digital infrastructure and carbon productivity. The impact and transmission mechanism between the new digital infrastructure and carbon productivity was also explored. The results were as follows: (1) The development level of the new digital infrastructure and the level of carbon productivity in the YREB showed a spatial differentiation, with an evolution trend of spatial mismatch. (2) The new digital infrastructure significantly improved carbon productivity, which was still valid after a series of robustness tests. (3) The new digital infrastructure could improve carbon productivity by promoting green technological innovation. The influence of the new digital infrastructure on carbon productivity showed an obvious spatial spillover effect. (4) The heterogeneity analysis showed that the positive promoting effect was more significant in non-resource cities and Chengdu-Chongqing urban agglomerations. These conclusions may provide new empirical evidence for promoting the realization of the“carbon neutral”goal towards a high-quality urban development.