Balancing economic development with environmental protection is central to achieving high-quality development. As a key measure for promoting industrial transformation and upgrading, the environmental governance effects of the pilot policy for innovative industrial clusters warrant in-depth examination. Based on panel data from 257 prefecture-level cities covering the period from 2010 to 2022, a multi-period difference-in-differences model was applied to systematically evaluate the impact of the innovative industrial cluster policy on urban environmental quality. The results indicate that the innovative industrial cluster policy significantly improves urban environmental quality. This conclusion remains valid after a series of robustness and endogeneity tests, including parallel trends tests, placebo tests, and PSM-DID. However, the policy effects exhibit significant heterogeneity, influenced by factors such as geographic location, resource endowments, the institutional foundation for environmental protection and the degree of marketization. Mechanism analysis reveals that the environmental optimization effects are primarily achieved through three pathways: incentivizing green technological innovation, guiding industrial restructuring, and leveraging the green transmission function of digitalization. Simultaneously, digitalization serves as a prerequisite for unlocking environmental dividends. Further analysis indicates that the environmental governance effects of this policy exhibit phased characteristics, with policy effectiveness showing a trend of diminishing marginal returns over time. From a spatial perspective, the policy pilot not only improved local environmental quality but also effectively reduced environmental pollution levels in neighboring areas, demonstrating positive spatial spillover effects. The conclusions provide empirical evidence for achieving synergistic governance between industrial development and environmental optimization under the new development paradigm, offering valuable insights for policymakers seeking to promote the development of innovative industrial clusters in a manner tailored to local conditions, unlock the potential of digital empowerment, and enhance the level of regional environmental governance.