Abstract:This paper analyzes the carbon emission reduction status in China's carbon emission trading pilot areas to provide empirical basis for the improvement of the current carbon emission trading pilot policies. Based on the panel data of 30 provinces in China from 2005 to 2019, the multi-period differential model was used to test the carbon emission reduction effect of pilot carbon emission trading policies, and the parallel trend test, placebo, PSM-DID and other methods were used to test the robustness of regression results. Through the mediation effect analysis, the transmission path of green technology innovation and energy structure transformation is tested. Finally, the regional heterogeneity of pilot policies is analyzed. The results show that: (1) the pilot policy significantly reduces the carbon emission and carbon emission intensity in the pilot area, and there is a significant carbon emission reduction effect; (2) Both green technology innovation and energy structure transformation are the pathways for pilot policies to achieve carbon emission reduction effect. Green technology innovation plays a role of 12.38% and 5.51% in reducing carbon emission intensity in pilot areas, and energy structure transformation plays a role of 3.74% and 0.47% in mediating effect, respectively. (3) The carbon emission reduction effect of Beijing is the strongest among the 6 pilot regions, followed by Shanghai and Tianjin, and the overall carbon emission reduction effect of Hubei and Chongqing is weak. The conclusions of the study provide the main enlightenment for better realizing the "dual carbon" goal, promoting the transformation of energy structure and green technology innovation, including strengthening the construction of national carbon market, and formulating differentiated carbon reduction policies according to local conditions.