There is a growing literature in exploring the economic impacts ofhigh-speed rails(HSR).Butlittle is known aboutthe geography implications from high-speed rail network expansions on local accessibility dynamics.This paper uses a market potential approach to examine the network structure and evolution of the rail transport network of China(RTNC)with a particular focus on high-speed rail improvements.Exposure to railroadnetwork expansions is measured by changes in “marketpotentials”---a reduced-form expression derived from the general equilibrium model of the geography literature.A key finding is that rail improvements tend to result in more spatially integrated network patterns for shifting accessibility improvements between core regions and periphery regions.This finding,albeit from a highly stylized market potential model,shows clear evidence about the network centralization trend and confirms the transforming of comparative location advantages between HSR-connected counties and other counties.The results point to the importance of HSR connections in the transformation of accessibility dynamics in non-metropolitan areas of China.