In the modern environmental governance system, strengthening environmental regulation is an inevitable choice for driving corporate green transformation. However, the rising costs of environmental compliance may also stimulate tax avoidance, posing a potential threat to the integrity of the national tax base. Meanwhile, the principle of “no penalty for first violation” in ecological environments, as an innovative practice of flexible environmental enforcement, raises a key question: Will the signal of flexible enforcement prompt firms to transfer compliance costs through tax avoidance, or will it foster cooperation expectations and psychological contracts that enhance tax compliance?

Drawing on a semantic analysis of 2013–2023 texts from the official WeChat accounts of 30 provincial ecological environment bureaus, this paper finds that the principle of “no penalty for first violation” exerts a stronger inhibitory effect on corporate tax avoidance in regions where the principle is viewed more favorably. In mechanism analysis, this paper integrates the cash holding theory with the theoretical framework of behavioral economics and information economics, examining the transmission effects of operating cost ratio, institutional investors’ attention, and regional business environments. Further analysis reveals that when flexible environmental enforcement is combined with two other types of environmental policies, it yields significant synergistic effects. Moreover, flexible environmental enforcement also changes the behavior patterns of firms and has a positive impact on market reputation and innovation investment.

This paper makes the following contributions: First, it extends the analytical scope of flexible enforcement research beyond market regulation and tax inspection into the environmental domain, providing unique empirical evidence for flexible enforcement reforms. Second, by building a theoretical bridge between environmental governance and corporate tax decisions, it illuminates the behavioral pathways through which flexible environmental enforcement affects tax compliance, expanding the interdisciplinary theoretical framework linking environmental policies and tax behaviors. Third, it innovates the measurement of law enforcement intensity by constructing a multi-dimensional semantic index based on massive official WeChat account texts, offering a replicable methodological reference for identifying causal relationships between policy text analysis and corporate behaviors.