Does the High-speed Rail Promote the Medium and Small Cities Innovation Output?

The operation of high-speed rail broke the urban barrier, compressed the space-time distance, and the innovation elements were reconfigured between cities, which had a polarized effect on the innovation output of different cities. From the perspective of city innovation factors, based on the double difference model, the data of 12 cities along the Datong-Xian high-speed railway in 2008-2016 were used to analyze the impact of high-speed rail opening on the innovation output of small and medium-sized cities along the line. The results show that the opening of high-speed rail can not effectively promote the innovation output of small and medium-sized cities, but it is a significant negative effect. Due to the siphon effect of large cities and the neglect of soft environment construction in small and medium-sized cities, the innovation factors of small and mediumsized cities are squeezed. Therefore, the innovation and development of small and medium-sized cities along the future will focus on improving the soft environment, retaining and introducing new talents, attracting the accumulation of innovative factors, and driving the rise of small and mediumsized cities along the high-speed rail. Keywords—high-speed railway; city innovation; difference-in -