改革开发以来，中国在经济增长方面取得了巨大成就。然而与此同时，高投资、高污染、高消耗的粗放型增长模式也导致了相对严重的资源和环境问题。为了改变这种以环境换取增长的不可持续道路，我国政府相继出台一系列环境规制政策与法规。提高企业环境规制强度是否必然制约企业发展，经济发展和环境保护是否必然相互矛盾，如何实现既要“金山银山”又要“绿水青山”的经济增长与环境保护的“双赢”模式，上述问题的解答对推动我国经济高质量发展有重要的现实意义。因此本研究探讨环境规制对企业全要素生产率的影响，并引入环保投资视角，探讨环保投资在环境规制到企业全要素生产率之间的作用。

      本研究以波特假说为理论依据，在对大量已有文献的梳理基础之上，选择2010-2019年传统重污染行业A股上市的企业样本进行实证分析：首先采用基准回归分析探讨环境规制与重污染企业全要素生产率的关系，其次采用非线性关系下的中介效应检验探讨企业环保投资的中间传导作用，最后从产权结构和地区因素两个角度进行异质性分析。

      主要研究结论：（1）环境规制与重污染企业全要素生产率之间呈“U”型非线性关系。环境规制最初的增强会首先导致企业全要素生产率降低，当环境规制达到一定程度之后，环境规制反而可以促进企业全要素生产率的提高。（2）环保投资在环境规制与企业全要素生产率之间起到一个中介作用。当环境规制力度增强，企业环保投资增加，从而企业全要素生产率得以提升。（3）在异质性分析中发现国有企业与非国有企业、东部企业与中西部企业呈现出不同的效应。即环境规制与国有企业TFP之间呈“U”型非线性关系，而在非国有企业样本两者之间没有显著的相关关系。相较于西部不发达地区，东部较发达地区的环境规制与企业全要素生产率之间的“U”型关系更为显著。

      根据研究结果，本研究从政府和企业的视角提出如下建议：政府应该适度提高环境规制强度、制定差异化的环境规制政策、适度进行对企业环保投资的财政补贴、鼓励公众参与监督；企业应该积极响应环境规制政策，国有企业应充分发挥国有企业标杆作用，由环境规制政策的被动接受者逐步转变为主动参与者，非国有企业也应积极践行新发展理念，紧跟国家政策走，实现环境保护与企业发展的双赢。主动、按时、全面、准确的披露企业环境保护信息，向政府与公众定时进行环境信息公开披露，积极展现企业自身承担社会环保责任的形象，吸引投资者的同时提高企业的竞争力。

      Since the reform and development, China has made great achievements in economic growth. However, at the same time, the extensive growth model featuring high investment, high pollution and high consumption has also led to relatively serious resource and environmental problems. In order to change this unsustainable road of exchanging environment for growth our government successively makes a series of environmental regulation policies and regulations. Whether increasing the intensity of enterprise environmental regulation will inevitably restrict the development of enterprises, whether economic development and environmental protection will inevitably contradict each other, and how to realize the “win-win” mode of economic growth and environmental protection that requires both “gold and silver mountains” and “clear water and green mountains”? The answers to the above questions are of great practical significance to promote the high-quality development of Chinese economy. Therefore, this study discusses the impact of environmental regulation on total factor productivity of enterprises, and introduces the perspective of environmental investment to discuss the role of environmental investment between environmental regulation and total factor productivity of enterprises.

      Based on Porter’s hypothesis and A large number of existing literatures, this study selected A-share listed enterprises in heavily polluting industries from 2010 to 2019 for empirical analysis: First, the relationship between environmental regulation and the total factor productivity of heavy polluting enterprises is discussed by baseline regression analysis. Second, the intermediate conduction effect of environmental protection investment in enterprises is discussed by using the intermediary effect test under the nonlinear relationship. Finally, the heterogeneity analysis is conducted from the property rights structure and regional factors.

      Main conclusions: (1) There is a U-shaped nonlinear relationship between environmental regulation and total factor productivity of heavily polluting enterprises. The initial enhancement of environmental regulation will first lead to the decrease of total factor productivity of enterprises. When environmental regulation reaches a certain degree, namely the inflection point, environmental regulation can promote the improvement of total factor productivity of enterprises. (2) Environmental investment plays an intermediary role between environmental regulation and total factor productivity of enterprises. When the intensity of environmental regulation is strengthened, enterprises’ investment in environmental protection will increase, thus improving the total factor productivity of enterprises. (3) In the heterogeneity analysis, it is found that state-owned enterprises and non-state-owned enterprises, eastern enterprises and central and western enterprises show different effects. That is, there is a U-shaped nonlinear relationship between environmental regulation and TFP of state-owned enterprises, while there is no significant correlation between the two in non-state-owned enterprise samples. Compared with the underdeveloped western region, the U-shaped relationship between environmental regulation and total factor productivity is more significant in the developed eastern region.

      According to the research results, this study puts forward the following suggestions from the perspective of the government and enterprises: the government should moderately improve the intensity of environmental regulation, formulate differentiated environmental regulation policies, moderately provide financial subsidies for enterprises’ investment in environmental protection, and encourage the public to participate in supervision; Enterprises should actively respond to environmental regulation policies, and state-owned enterprises should give full play to their role as benchmarking enterprises, gradually change from passive recipients of environmental regulation policies to active participants, and lead the green and low-carbon transition. Non-state-owned enterprises should also actively practice the new development concept, keep up with national policies, and achieve a win-win situation between environmental protection and enterprise development. Active, timely, comprehensive and accurate disclosure of enterprise environmental protection information. Regular public disclosure of environmental information to the government and the public, actively show the image of the enterprise to undertake social environmental responsibility, attract investors and improve the competitiveness of the enterprise.