Based on the literature review，this study explored the mechanism of high?speed railway on knowledge spillovers. Using thepatent panel data of 30 provinces in China from 2003 to 2020，the spatial agglomeration characteristics of China’s knowledge outputthrough Moran’s I was described，and a spatial econometric model was built to empirically study the impact effect and spillovers distance of high?speed railway on China’s inter?provincial knowledge spillovers. The study demonstrated：① The spatial distribution of China’s patents presents spatial agglomeration from 2008 to 2015，and the agglomeration is increasing，and the agglomeration gradually tends to be gentle after 2015；② High?speed railway has a significant positive impact on inter?provincial knowledge spillovers in China，and the impact is increasing with the improvement of railway network；③ There is a certain distance limit for the impact of high?speed railway on the knowledge spillovers among provinces in China. Specifically，the distance limit for China’s high?speed railway in 2012 is 2，096 kilometers，with the error range not exceeding 29 kilometers；In 2017，the effective limit distance is 2，188 kilometers，with the error range not exceeding 63 kilometers. With the development of high?speed railway，the limit distance is expected to increase year by year. Based on the research conclusions，this study puts forward some countermeasures and suggestions on reasonably promoting the coordinated promotion and balanced development of high?speed railway and knowledge spillovers.