Based on panel data from 30 provinces and cities in China from 2005 to 2021, a systematical calculation has been made of the marginal cost of carbon dioxide reduction in China’s industry, which is used as the dependent variable to explore the impact direction and influencing factors of carbon emission trading policies on China’s industrial low-carbon transformation by adopting a multi-time point double difference model. The research results indicate that the pilot policies of carbon emission trading rights exert a significant positive impact on the low-carbon transformation of China’s industrial sector. In addition, carbon intensity, industrial structure, regional R&D level, and the number of industrial enterprises have a negative impact on the marginal cost of industrial carbon dioxide reduction.