摘要:China has launched a carbon (CO2) emissions trading market to cope w ith the increasing deterioration of air pollution. CO2 emissions trading is an im portant policy option for China under the pressure of energy saving and emission reduction. Whether CO2 emissions trading can reduce the intensity of CO2 emission or how much CO2 emission intensity can be reduced s till requires further study. Theoretical analysis shows that CO2 emissions trading positively affects the reduction of CO2 emission intensity, but credible empirical support is lim ited. Moreover, a “ quasi-natural experiment” is constructed using Guangdong province as an example, and the net effect of CO2 emissions trading policy on the industry CO2 emission intensity is validated using the panel data of Guangdong province from 2000 to 2016 to establish a difference-in-differences model (DID). The analysis shows that the average net effect of CO2 emissions trading on CO2 emission intensity is significantly negative, and its marginal effect increases w ith time. A series of robustness tests is conducted to illustrate the reliability of the results.