Abstract: The key to promoting infrastructure construction in the new era lies in improving quality and efficiency, coordinating traditional and new infrastructure planning, so as to enable high-quality economic development. Based on the above realistic background, this article first adopts a new economic geography model to reveal the theoretical mechanism that infrastructure upgrades promote entrepreneurship by reducing entrepreneurial costs. In the empirical analysis, the micro data of enterprise industrial and commercial registration information and venture capital cases in 265 prefecture level cities from 2005 to 2017 were sorted out. Combined with China's digital inclusive financial index and other traditional variables, the opening of high-speed rail and the construction of smart city were used as quasi natural experiments for the upgrading of transportation and new infrastructure respectively, The following conclusions are drawn through the difference in difference model: (1) the opening of high-speed railway and the construction of smart city have significantly improved entrepreneurship. From a subregional perspective, the former has a more positive impact on large cities in the East, and the latter can help small and medium-sized cities in the central and western regions make up for the weak effect of the former（2) The indirect verification of the mechanism shows that the opening of high-speed railway improves the flow of venture capital, an element of entrepreneurial ecosystem, and the construction of smart city promotes entrepreneurship through the inclusive nature of digital economy. This study provides a basis for how to effectively use the supporting role of infrastructure "hardware" to stimulate and protect entrepreneurship in the new era.
