This paper quantifies the multifold economic impacts of high-speed railway (HSR) in China. Firstly, the effect of introducing HSR on the prefecture-level gross regional product (GRP) is investigated using the difference-in-differences method. Results show that HSR inauguration has positive effects on economic development. Secondly, the effect of proximate HSR station density is examined. We find that when taking into account the density of HSR stations near a city, the existence of a HSR station in its own realm is insignificant; instead, the station density plays a significant role in the regional economic growth. This indicates that as long as the city is located in an area with high density of HSR stations, whether it possesses HSR is less important. Thirdly, the heterogeneity of economic impact is studied by categorizing cities by 2017 GRP, which demonstrates that HSR has larger positive impacts on the wealthier regions.