As an important measure of enterprise governance, internal control can enhance the organizational rationality of the enterprise, ensure that the enterprise consciously assumes social responsibility for the protection of the natural environment and resources, and promote the sustainable development of the national economy. Using data from China's A-share heavy pollution industry listed companies from 2009 to 2018, this study explored the relationships among internal control quality, enterprise environmental protection investment, and financial performance. The results show that the quality of internal control has a significant positive impact on enterprise environmental protection investment and financial performance. Enterprise environmental protection investment has a significant positive impact on financial performance and plays a partial intermediary role in the positive impact of internal control quality on financial performance. While expanding the theory of resource-based concepts, this study clarified the positive impact of corporate environmental management and practical behavior on corporate value and provides a theoretical basis for companies to actively implement environmental protection responsibilities, strengthen internal environmental management capabilities, and enhance corporate value. At the same time, it also provides a basis for the government to issue relevant environmental protection policies, strengthen enterprise internal control construction guidelines, and encourage third-party organizations to evaluate the effectiveness of enterprise internal control.
Keywords: environmental protection investment; environmental sustainability; financial performance; heavy pollution industry; internal control.