Infrastructure development is a critical means of maintaining and revitalizing economic growth and is an important driver of economic recovery. An indicator system for infrastructure development was constructed to examine the theoretical mechanism and heterogeneity of the impact of the“Belt and Road”initiative on infrastructure development in cities along China’s borders. Using panel data from 278 Chinese cities from 2010 to 2020 and employing the difference-in-differences method，the impact，mechanism，and heterogeneity of the“Belt and Road”initiative on infrastructure development in these cities were empirically examined. The“Belt and Road”initiative promoted infrastructure development in Chinese cities along its borders，and this conclusion was robustly supported by parallel trends tests，placebo tests，and other tests. The“Belt and Road”initiative had a positive impact on infrastructure development in these cities through its effects on scientific and technological innovation and industrial structure upgrading. The promotion effect of the“Belt and Road”initiative on infrastructure development varied significantly between cities along the“Belt”and the“Road，”with the policy effect being significantly stronger in“Belt”cities than in“Road”cities. Further research revealed that the effect of scientific and technological innovation was mainly manifested in“Belt”cities，while the effect of industrial structure upgrading was mainly manifested in“Road”cities. Infrastructure development in cities along the“Belt and Road”had a“siphoning effect，”which led to negative spatial spillover effects. The findings provide a new perspective for exploring economic recovery and growth points，enrich the study of the factors influencing infrastructure development，and provide theoretical and empirical evidence for the government to fully leverage the role of the“Belt and Road”initiative and formulate infrastructure development strategies. They also offer policy implications for the government to promote the high-quality development of an open economy.