This paper selects the panel data of 297 cities in China from 2003 to 2017 and analyzes the effects of government efficiency and innovation environment on the relationship between high-speed rail opening and economic growth from the perspective of government competition pressure and information flow by using the approach of difference-in-differences (DID). The findings are as follows: first, the opening of high-speed rail has a significant promoting effect on regional economic growth; second, government efficiency has negative impact on the relationship between high-speed rail development and economic growth, while the innovation environment has positive impact on this relationship; third, the moderating effects of government efficiency and innovation environment exhibit regional heterogeneity. This paper provides a new perspective from the perspectives of government competition pressure and information flow for understanding the impact of high-speed rail on the economy, offering insights for promoting the coordinated and sustainable development of the Chinese economy.