面对环境问题，我国始终坚持绿色发展理念，并提出“双碳”目标。为实现这一目标，我国出台了碳排放权交易制度等一系列环境规制政策。研究政策效果，是完善环境规制政策，实现绿色发展的重要手段。绿水青山就是金山银山，既要绿水青山，也要金山银山。政策实施既要关注环境效果，同时也应注重经济效率。碳排放权交易制度的“双赢效应”就是指环境保护与生产效率的同时提升，该制度是否具有环境与经济的“双赢效应”就是绿水青山与金山银山是否能够兼得的政策表现。只有实现经济与环境双赢，才能真正实现高质量发展。因此，研究碳排放权交易制度的政策效果，验证其是否能够实现企业碳减排与提高全要素生产率的双赢，对未来该制度的全面推行，提出更有效的环境规制措施，推动中国经济高质量发展，构建人与自然命运共同体至关重要。

本文基于A股上市公司数据，选取2009-2020年高污染企业数据为样本，将碳排放权交易试点政策作为准自然实验，将企业全要素生产率和企业碳排放强度作为被解释变量，利用双重差分模型，研究碳排放权交易制度是否能够在降低企业碳排放强度的同时提高企业全要素生产率，以检验该政策是否具有“双赢效应”，并通过动态回归进一步检验政策效果，从平行趋势检验，安慰剂检验，PSM-DID检验和替换被解释变量四个方面对其结论进行稳健检验。其次，利用中介效应模型检验该政策实现“双赢效应”的传导机制。最后，通过异质性分析，研究不同企业，行业和地区的政策效果。

实证研究表明：碳排放权交易制度具有经济与环境的“双赢效应”，即能够在实现企业碳减排的同时提高企业全要素生产率。动态回归后，该结论仍然成立，且通过了平行趋势，安慰剂，PSM-DID，替换被解释变量四种检验。进一步研究表明，碳排放权交易制度通过促进企业绿色技术创新提高企业全要素生产率，降低企业碳排放强度，从而实现“双赢效应”。异质性分析发现：企业方面，该制度对于非国有企业比国有企业，小规模企业比大规模企业，“双赢效应”更明显。行业方面，该制度对高碳行业的碳减排效果优于低碳行业，但对其提高全要素生产率的效果弱于低碳行业。地区差异性方面，政策落实程度高的地区能实现“双赢效应”，政策落实程度低的地区则不能实现“双赢效应”。

In the face of environmental problems, China has always adhered to the concept of green development and put forward the goal of "double carbon". In order to achieve this goal, China has introduced a series of environmental regulation policies such as carbon emission trading system(CET). Research on policy effects is an important means to improve environmental regulation policies and achieve green development. Green water and green mountains are golden mountains and silver mountains, which should be both green water and green mountains. Policy implementation should not only focus on environmental effects, but also on economic efficiency. Whether the carbon emission trading system has the "win-win effect" of environment and economy is the policy performance of whether the green water and green mountains and the golden mountains and silver mountains can be achieved simultaneously. Only by achieving a win-win situation between the economy and the environment can we truly achieve high-quality development. Therefore, it is very important to study the policy effect of the carbon emission trading system, verify whether it can achieve a win-win situation of enterprise carbon emission reduction and total factor productivity, put forward more effective environmental regulation measures for the full implementation of the system in the future, promote the high-quality development of China's economy, and build a community of shared future for human and nature.

Based on the data of A-share listed companies, this paper selects the data of high-polluting enterprises from 2009-2021 as a sample, takes the CET as a quasi-natural experiment, takes the total factor productivity of enterprises and the carbon emission intensity of enterprises as the explanatory variables, and uses the double difference model to study whether the carbon emission trading system can reduce the carbon emission intensity of enterprises while improving the total factor productivity of enterprises, To test whether the policy has a "win-win effect", and to conduct a robust test of its conclusions from four aspects: parallel trend test, placebo test, PSM-DID test and replacement of the explained variables. Secondly, the intermediary effect model is used to test the transmission mechanism of the "win-win effect" of the policy. Finally, the policy effects of different enterprises, industries and regions are studied through heterogeneity analysis.

The empirical research shows that the carbon emission trading system has the "win-win effect" of economy and environment, that is, it can improve the total factor productivity of enterprises while achieving carbon emission reduction. After passing a series of robustness tests the conclusion is still valid. Further research shows that the carbon emission trading system can improve the total factor productivity of enterprises and reduce the carbon emission intensity of enterprises by promoting technological innovation of enterprises, thus achieving a "win-win effect". The heterogeneity analysis found that the "win-win effect" of the system is more obvious for non-state-owned enterprises than for state-owned enterprises, and for small-scale enterprises than for large-scale enterprises. In terms of industry, the effect of the system on carbon emission reduction of high-carbon industries is better than that of low-carbon industries, but its effect on improving total factor productivity is weaker than that of low-carbon industries. In terms of regional differences, regions with high degree of policy implementation can achieve "win-win effect", while regions with low degree of policy implementation cannot achieve "win-win effect".