It is essential for achieving green and sustainable economic development by using tax incentives to promote green investment. Using the data from the seventh, eighth, ninth, and tenth Chinese Private Enterprise Surveys (CPESs) conducted by the Private Enterprise Research Group and using China’s corporate income tax reform in 2008 as a quasi-natural experiment, this paper empirically analyses the effect of tax incentives on corporate green investment based on the difference-in-difference models. The research results show that tax incentives can significantly increase corporate green investment. The mechanism test shows that easing financing constraints is an important channel for tax incentives to promote corporate green investment. In addition, the role of tax incentives in promoting green investment varies depending on the type and location of the enterprise. Relatively speaking, tax incentives have a stronger effect in promoting green investment for corporates with low sales revenue, located in the eastern region, heavy pollution, and high innovation capability. By doing placebo tests and changing measurement methods of indicators for robustness tests, the conclusions of this paper are still valid. Therefore, the government should increase tax incentives to better promote corporate green investment.

This study examines whether China’s high-tech enterprise identification policy promotes corporate sustainable innovation. Using panel data from Chinese listed firms on the Shanghai and Shenzhen stock exchanges between 2008 and 2022, we adopt a time-varying difference-in-differences (DID) model to evaluate the policy’s effectiveness and explore its underlying mechanisms. The results reveal that this certification policy significantly facilitates green innovation, and the findings remain robust across various checks, including alternative measurements, placebo tests, propensity score matching DID (PSM-DID), and the exclusion of digital transformation trend and confounding macro-level policies. Mechanism analysis shows that the policy influences green innovation by alleviating financing constraints, increasing access to government subsidies, facilitating the agglomeration of scientific and technological talent, and encouraging greater R&D investment. Heterogeneity analysis further indicates that the policy effect is more pronounced among non-state-owned enterprises, small-scale firms, capital-intensive businesses, those located in high-institutional-quality regions, and firms in China’s eastern provinces. Moreover, the positive impact is strongest for growth-stage firms. The policy has also been found to improve green innovation efficiency. These findings offer empirical insights for optimizing selective industrial policies to enhance sustainable innovation and support China’s dual-carbon goals.