In the context of the "dual carbon" goals, the coordinated development of digitization and greenization has become an important driver for high-quality economic development in China. Firstly, based on endogenous growth framework, this study expands upon the enterprise pollution reduction model proposed by Shapiro & Walker (2018), distinguishing between the technological progress effect and green innovation effect on carbon emission intensity reduction in manufacturing companies due to digitization. The corresponding theoretical hypotheses are put forward. Secondly, using the data of manufacturing companies listed on the Shanghai and Shenzhen stock Exchanges from 2011 to 2019 as the benchmark, empirical tests are conducted to examine the impact of digitization on carbon emission intensity in the manufacturing sector. The existence of two mechanisms, namely, productivity improvement through digitization and green innovation, is confirmed. Furthermore, heterogeneity research reveals that at the regional level, digitization inhibits the increase in carbon emission intensity in the eastern and central regions, but this inhibitory effect is not significant in the western region. At the industry level, digitization has a deeper impact on emission reduction in technology and capital-intensive manufacturing industries. Moreover, the green innovation effect is significantly present in the eastern region and in technology and capital-intensive manufacturing clusters, whereas the technological progress effect is not evident in the grouped regression analysis. The research findings provide empirical evidence for accurately assessing the emission reduction effect of digitization and formulating differentiated policies for digital empowerment of the manufacturing industry in its green and low-carbon transformation.