数字基础设施建设能促进城市创新质量提升吗？--来自"宽带中国"试点政策的证据

igital infrastructure construction is the support for promoting digital economy and innovative city construction, and improving innovation quality is the key to driving high-quality economic development. Based on the panel data of 275 prefecture-level cities from 2011 to 2020, this paper analyzes theoretically the influence path of digital infrastructure construction on urban innovation quality, and constructs an asymptotic double-difference model with the pilot policy of "Broadband China" as a quasi-natural experiment, to systematically investigate the influence effect of digital infrastructure construction on urban innovation quality. The results of the study show that digital infrastructure construction has a significant impact on the quality of urban innovation. The results of the study show that digital infrastructure construction has a significant effect on urban innovation quality, and this conclusion still holds after a series of robustness tests; mechanism analysis shows that digital infrastructure construction promotes urban innovation quality through promoting the development of digital finance, stimulating urban entrepreneurial activity, and reinforcing the strategic leadership of the government; and the analysis of heterogeneity shows that digital infrastructure construction has a significant effect on urban innovation quality, and this conclusion still holds after a series of robustness tests. Heterogeneity analysis shows that the enhancement effect of the "Broadband China" pilot policy on the quality of urban innovation is more obvious in cities with better geographic location, higher administrative hierarchy, low resource endowment, and high human capital density. The findings of this paper have important policy implications for promoting the construction of digital China and further promoting the innovation-driven development strategy.