This study examines whether China’s Industrial Internet pilot policy (2017–2023) enhances firm innovation and explores the underlying mechanisms. Exploiting the staggered rollout of the policy across provinces as a quasi-natural experiment, we find that Industrial Internet adoption significantly increases firms’ innovation output. Mechanism tests show that the policy promotes knowledge accumulation, strengthens innovation persistence, and improves human capital allocation. We also document positive economic consequences, as treated firms earn higher returns to innovation. The effects are stronger for capital-intensive firms, those located in regions with advanced digital infrastructure, and firms undertaking joint or substantive innovation activities. Overall, the evidence highlights the Industrial Internet as an effective catalyst for firm innovation by deepening R&D capability and facilitating cross-industry knowledge flows.