This paper uses the Environmental Protection Tax Law as a quasi-natural experiment for tax greening and constructs a DID model to systematically examine how tax greening affects the entry of green investors. The study finds that the implementation of the Environmental Protection Tax Law helps attract green investors to enterprises, and this promotion effect is more pronounced in sample enterprises with better external information environments and financing environments, environmentally-savvy executives, and higher quality of internal controls. Reducing government environmental subsidies, strengthening media supervision and attention, increasing corporate environmental investment, and improving the level of environmental information disclosure are important channels through which the Environmental Protection Tax Law promotes the entry of green investors into enterprises. Further analysis reveals that the entry of green investors has a positive impact on corporate green innovation, green TFP, and ESG standards, while also positively affecting corporate economic benefits and enhancing the level of corporate profitability and TFP. This paper provides new evidence for the research on whether tax greening can boost corporate green development, enriches the study of the micro-policy effect of tax greening, and also offers useful references from the perspective of green investors for promoting enterprises to achieve dual economic and environmental benefits.