How Environmental Protection Tax Promote Green Innovation? —The Moderating Role of Digital Transformation and Dual Driving Pathways

Under the background of coordinated promotion between dual-carbon goals and digital economy , how enterprises can balance green innovation with economic benefits through environmental regulation, while leveraging digital transformation to drive green development, has become a critical issue. This study treats China's 2018 environmental protection tax (EPT) implementation as a quasi-natural experiment, employing difference-in-differences (DID) to examine its impact on corporate green innovation. Key findings:(1) EPT significantly promotes green innovation, with stronger effects on substantive innovation than strategic innovation; (2) Digital transformation shows a U-shaped moderating effect, which indicate that the impact of environmental protection tax on corporate green innovation varies across different stages of digital transformation; This study reveals the effects of EPT in driving corporate green innovation through dual pathways, providing practical references and management implications for achieving coordinated 'digital - green' development.