<p>Carbon emission efficiency (CEE) improvement is an effective approach to promote sustainable economic development. In the digital age, digital infrastructure serves as a new engine for economic development. However, whether digital infrastructure can effectively improve CEE remains unclear. Based on panel data from 30 Chinese provinces spanning 2009–2022, we investigated the nexus between digital infrastructure, heterogeneous industrial agglomeration, and CEE using Spatial Durbin modeling. Two scenarios were designed to predict China’s CEE over the next decade. The results showed that (1) China’s CEE generally displayed an upward trend from 2009 to 2022, with obvious regional differences and a decreasing trend in the east, center, and west; (2) the relationship between digital infrastructure and CEE was U-shaped, and the agglomeration of manufacturing and producer services significantly increased CEE; (3) manufacturing agglomeration caused by digital infrastructure enhanced CEE, while producer services agglomeration resulting from digital infrastructure had the opposite effect; (4) China’s CEE will continue to rise over the next decade, and it can be improved through digital infrastructure development and industrial agglomeration. These findings will help policymakers determine the optimal placement for digital infrastructure development and the spatial distribution of industries.</p>