This study estimates the causal impact of digital infrastructure development on attracting advanced service industry entrepreneurs, leveraging the staggered implementation of the 'Broadband China' policy as a quasi-experiment. Applying a multi-period Difference-in-Differences (DID) model, we find that the policy significantly enhanced the inflow of these entrepreneurs. Our analysis provides a nuanced perspective by identifying key mediating pathways: expanding the digital market size, fostering entrepreneurial space agglomeration, and enhancing urban innovation capacities. These findings empirically justify continued digital infrastructure investment, underscoring its critical role in regional economic upgrading and offering valuable empirical insights for policy development.