Abstract:    Environmental protection tax is an important environmental and economic policy in China, which is conducive to promoting China′s green transformation and development. But for a long time, China only implemented a system of pollution fees. Due to the mandatory and normative defects of the pollutant discharge fee system itself, it is difficult to realize the expected economic and environmental effects. Therefore, in order to promote the construction of ecological civilization, accelerate the green transformation development, and realize the win-win situation of economic development and environmental protection, the Environmental Protection Tax Law was officially implemented on January 1, 2018.Existing studies have shown that environmental tax can achieve environmental dividends, but whether it can achieve economic and social dividends is still controversial. The implementation of the policy of changing fees and taxes provides a realistic scenario for the study of the economic consequences of environmental protection tax. Therefore, whether environmental protection tax can promote the green development of enterprises and achieve a win-win situation of environmental protection and economic development is a practical problem worth in-depth analysis and discussion. This paper attempts to explore the impact of environmental protection tax on the green development of enterprises and its mechanism of action, which has important practical significance for the comprehensive study of the policy effect of environmental protection tax and the improvement of the supporting policies for the green development of enterprises.This paper took the implementation of the Environmental Protection Tax Law since 2018 as a quasi-natural experiment, and the A-share listed enterprises in Shanghai and Shenzhen from 2013 to 2021 as research samples, and used the difference-in-differences-in-differences (DDD) model to empirically investigate the impact and mechanism of environmental protection tax reform on the green development of enterprises.It was found through this study that the environmental protection tax reform can significantly promote the green development of enterprises, and the impact of regional differentiated tax reform on urban environmental quality has a green "trickle-down effect". Further analysis showed that the environmental protection tax reform is more significant to the green development of non-state-owned enterprises and enterprises in regions with low marketization degree. According to the mechanism test, the reform of environmental protection tax affects the green development of enterprises mainly by encouraging enterprises to increase investment in environmental protection, strengthening green technology innovation and improving the efficiency of resource allocation. The research results have clarified the impact and mechanism of environmental tax on enterprises′ green transformation and development, theoretically enriched the interaction research between macro fiscal and tax policies and micro enterprises′ green behavior, expanded the research on micro economic consequences of environmental tax reform, and in practice, will apply market-based environmental regulation tools to local governments and enterprises. It will provide important inspiration for promoting green development of regions and enterprises.The main contributions may be reflected in the following three aspects: First, this paper has examined for the first time the micro-mechanism of environmental protection fee and tax change affecting the green development of enterprises, and it will provide micro-evidence for the existing provincial or industrial level research. Second, this paper has used the DDD model to study the policy effect of the green total factor productivity of enterprises, which is more in line with the goal of environmental protection fee and tax reform, will deepen the understanding of the impact of environmental protection fee and tax reform on the green development of enterprises, and enrich the research on the policy effect of environmental protection fee and tax reform. Third, this paper has deeply examined the mechanism and heterogeneity of environmental protection tax affecting enterprises′ green development, which can provide theoretical basis for national ecological civilization construction and the realization of the "two-carbon" strategic goal to formulate environmental regulation policies.

Key words: environmental protection tax, green development, difference-in-differences-in-differences (DDD)