Improving total factor productivity (TFP) is essential to achieving high‐quality and sustainable economic development. The existing literature mainly focuses on the impact of traditional infrastructure on TFP but generally ignores the role of new digital infrastructure in TFP and does not test impact mechanisms and whether there is heterogeneity in effects. Using panel data of 30 regions in China from 2006 to 2017, this paper analyzes the impact of new digital infrastructure on TFP and its mechanisms. The results are as follows: (1) New digital infrastructure can significantly improve regional TFP. After the robustness test, the results still support the findings. (2) New digital infrastructure can promote technological innovation, optimize factor allocation, and achieve economies of scale, thus improving TFP. (3) Further analysis shows that the positive effect of new digital infrastructure on TFP shows significant heterogeneity. In regions with high economic development levels, high research and development (R&D) levels, and high traditional infrastructure development levels, the positive effect of new digital infrastructure on TFP is more obvious. These findings not only enrich the literature on digital infrastructure and economic growth but also serve as a reference for governmental departments as they optimize their strategy for developing digital infrastructure and realizing sustainable economic development.