Against the dual backdrop of data element market development and corporate green transformation, understanding how data assetization affects corporate environmental investments at the micro level is crucial for guiding sustainable practices and building a data-driven environmental governance system. Using data from China’s A-share listed companies from 2009 to 2023, this paper systematically examines the effects, mechanisms, and boundary conditions of data assetization on corporate environmental investments. The study finds that data assetization significantly increases environmental investments by reshaping corporate resource bases and governance structures. Mechanism testing reveals that data assetization facilitates green credit through verifiable green credentials and attracts green investors via transparent operations, thereby easing resource constraints and strengthening environmental supervision. Heterogeneity analysis shows stronger effects under stricter regulations, better digital infrastructure, and stronger internal environmental orientation (e.g., high pollution intensity, executive awareness), highlighting contextual dependence. Notably, self-use data assetization mainly drives front-end preventive investments, while transactional data assetization may suppress end-of-pipe remedial investments due to attention diversion. This paper offers micro-level evidence for data-driven green transformation and provides insights for policymakers and firms in tailoring data governance and investment strategies.